Genetic testing and intellectual disability: what the evaluation can establish
Genetic testing for intellectual disability is a medical investigation that searches for a chromosomal or molecular explanation for a person's developmental and cognitive differences. The central clinical question is whether a detectable genetic change accounts for the person's history of intellectual and adaptive difficulties, contributes to associated medical findings, or identifies health risks that require attention. Testing may provide a molecular diagnosis, clarify recurrence risks, guide surveillance, and connect families with syndrome-specific resources. Its ability to do so depends on the phenotype, the technology used, the quality of interpretation, and the state of scientific knowledge. A negative result does not rule out a genetic cause, and a genetic result does not replace psychological assessment or define a person's abilities, character, or future. Current pediatric guidance supports early consideration of exome or genome sequencing, with chromosomal microarray and targeted investigations selected according to the clinical circumstances (American Academy of Pediatrics, 2025; Manickam et al., 2021).
The evaluation involves several distinct questions. Has intellectual disability or global developmental delay been clinically recognized? Does the pattern of medical and developmental findings suggest a particular genetic condition? Which test can detect that condition reliably? If a variant is found, is there sufficient evidence that it explains the person's presentation? Would knowing the answer affect care, family decisions, or access to appropriate support? Good genomic practice makes these questions explicit before testing and revisits them when results become available.
The clinical condition and the etiologic question
Intellectual disability is characterized by significant limitations in intellectual functioning and adaptive behavior arising during the developmental period. Intellectual functioning concerns abilities such as reasoning, learning, and problem-solving. Adaptive behavior encompasses conceptual, social, and practical skills used in everyday life. The American Association on Intellectual and Developmental Disabilities defines developmental onset operationally as before age 22 and emphasizes cultural context, communication accessibility, personal strengths, and sustained individualized supports (AAIDD, Defining Criteria). Clinical systems such as DSM-5-TR and ICD-11 use related but separately specified diagnostic frameworks. In young children who cannot yet undergo reliable formal assessment, global developmental delay may be the more appropriate clinical designation.
A genetic etiology is a causal or contributing biological explanation. It is not itself the psychological diagnosis. An individual may meet intellectual-disability criteria without a molecular finding, and someone with a pathogenic variant associated with neurodevelopmental disability may have a substantially different functional profile from others with the same condition. Establishing intellectual disability requires developmental history, assessment of intellectual abilities and adaptive functioning, and clinical judgment. A blood or saliva genomic test cannot measure those functions. Likewise, identification of an environmental, prenatal, or neurological contributor does not automatically rule out a coexisting genetic condition (AAP, 2025; AAIDD).
Who may benefit from etiologic genetic evaluation?
Evaluation may be considered for a child with unexplained global developmental delay or intellectual disability, and for adolescents or adults with an unresolved developmental history. The case becomes particularly informative when there are congenital anomalies, distinctive physical features, epilepsy, abnormal growth, a movement disorder, regression, sensory impairment, unexplained organ disease, or relatives with similar histories. Yet recognizable syndromic features are not required for testing: many molecular causes present principally through development, behavior, or learning. A clinician should discuss genomic evaluation even when a previous assessment established a disability diagnosis years earlier without determining its cause (AAP, 2025).
The indication differs from population screening, prenatal screening, consumer ancestry testing, and predictive testing in healthy relatives. In the clinical setting the patient already has a relevant phenotype, and the test is chosen to investigate it. Testing of family members may subsequently help interpret inheritance or provide reproductive information, subject to consent and the family's preferences.
How the genetic evaluation begins
Developmental history, examination, and phenotyping
A careful history is the foundation of test selection and interpretation. Clinicians document early milestones, learning trajectory, communication, adaptive development, neurologic signs, pregnancy and birth history, relevant exposures, hearing and vision findings, growth, physical examination, medical diagnoses, and a three-generation family history when feasible. Timing matters: stable developmental differences, progressive loss of abilities, and abrupt acquired cognitive change suggest different diagnostic pathways. Developmental regression, seizures, or new neurological symptoms call for assessment of medical causes without waiting for genomic results.
Phenotyping means describing observable clinical characteristics in accurate, specific terms. For example, epilepsy type, head-growth trajectory, hypotonia, congenital heart disease, and unusual movement patterns may make particular genes more plausible. In an apparently nonsyndromic presentation, broad sequencing may be more efficient than repeated single-gene tests. Updated clinical details also improve future reinterpretation when a first test is nondiagnostic (AAP, 2025).
Related medical investigations
Hearing and visual assessments, neurologic examination, targeted metabolic tests, and sometimes neuroimaging can reveal conditions with immediate implications for care. Biochemical investigation is especially pertinent if there is regression, episodic deterioration, organ involvement, unusual odors, movement abnormalities, or another phenotype consistent with a potentially treatable metabolic disorder. An urgent clinical concern requires timely specialist evaluation. Genetic testing supplements this process; sequencing cannot substitute for physical examination, developmental measurement, or all biochemical investigations (AAP, 2025).
The principal kinds of genetic tests
Chromosomal microarray
Chromosomal microarray analysis, or CMA, detects many clinically significant deletions and duplications of DNA known as copy-number variants. Depending on the platform, it may also identify regions of homozygosity that support further investigation of recessive or imprinting-related conditions. CMA generally does not reveal balanced rearrangements, single-nucleotide sequence changes, or repeat expansions. It has traditionally served as a broad first-line test in unexplained developmental disability. The 2025 AAP report describes an estimated diagnostic yield of roughly 15%–20% in relevant pediatric GDD/ID populations, while emphasizing that yield depends on case selection and methodology (AAP, 2025).
CMA continues to be useful when copy-number analysis is important, especially alongside exome sequencing that does not adequately evaluate deletions and duplications. Some genomic sequencing platforms can detect copy-number variation well enough to alter the need for a separate microarray; laboratories differ, so the capabilities of the actual assay should be reviewed rather than inferred from its name.
Exome sequencing
Exome sequencing reads most of the protein-coding portions of the genome, where many known disease-associated single-nucleotide changes and small insertions or deletions occur. It can examine many candidate genes in one investigation and is appropriate for genetically heterogeneous neurodevelopmental presentations. However, capture and sequencing depth vary; some exons are incompletely covered, and the test may not reliably detect certain structural variants, repeat expansions, methylation disturbances, deep intronic variants, or low-level mosaicism. Optional copy-number calling differs by laboratory. A report of a negative exome therefore describes what the test analyzed and found at a particular time, not everything that could be present in the genome (AAP, 2025; MedlinePlus Genetics, Sequencing).
Genome sequencing
Genome sequencing analyzes coding and noncoding DNA and can improve detection of certain variant classes, including structural changes, depending on the platform and interpretation pipeline. It may offer greater etiologic yield than exome sequencing, but sensitivity is not uniform across repeats, methylation-related conditions, mosaic variants, mitochondrial DNA, and complex structural regions. Short-read and long-read technologies differ in what they capture well, their costs, and their clinical availability. A more comprehensive assay does not eliminate the need to match findings to phenotype and to validate complex variants when indicated (AAP, 2025).
Trio sequencing and family samples
A trio typically includes the person being evaluated and both biological parents. Comparing samples can reveal a new, or de novo, variant in the child, show whether two variants lie on opposite copies of a gene, and help assess whether a candidate change segregates with disease. It can reduce uncertainty and improve diagnostic interpretation. A duo or proband-only approach is still possible when parents are unavailable or participation is not desired. Family sampling raises questions about biological relationships and incidental familial findings that should be discussed before specimens are collected (AAP, 2025).
Targeted tests: repeats, imprinting, and known syndromes
A clinical suspicion of a specific syndrome may justify targeted tests early, regardless of the broad sequencing strategy. Fragile X syndrome is associated with an FMR1 CGG repeat expansion that ordinary exome sequencing and conventional microarray generally do not diagnose. Conventional genome sequencing also cannot be assumed to assess it unless the laboratory offers a validated repeat-expansion analysis. Imprinting and methylation disorders likewise require methods designed for their molecular mechanisms. Conventional karyotyping can remain useful when balanced chromosomal rearrangement or a particular chromosome architecture is suspected. Mitochondrial testing, enzyme analysis, and tissue-specific investigations may be necessary for selected presentations (AAP, 2025).
A single-gene assay or narrow panel can be appropriate when examination suggests a recognizable disorder, a family carries a known pathogenic variant, or the laboratory offers especially strong technical coverage for a small set of relevant genes. Broad gene panels are not interchangeable: gene content, variant classes, interpretation policies, and reanalysis services vary. The important comparison is between the actual assays available to the patient, not marketing categories (MedlinePlus Genetics, Types).
What current professional guidance recommends
The American College of Medical Genetics and Genomics issued an evidence-based guideline in 2021 strongly recommending that exome or genome sequencing be considered as a first- or second-tier test in pediatric patients with congenital anomalies, developmental delay, or intellectual disability. That recommendation rested on diagnostic yield, clinical utility, and evidence that early sequencing can sometimes reduce the costs and delays of sequential testing (Manickam et al., 2021).
The American Academy of Pediatrics updated its clinical report in June 2025. For many children with GDD/ID whose examination does not identify a specific syndrome, it recommends exome or genome sequencing as a first-tier approach. If exome sequencing is chosen, CMA is part of the first-tier algorithm, performed sequentially or concurrently according to the case and the exome platform's copy-number capabilities. With genome sequencing that provides adequate copy-number assessment, a separate CMA may often be deferred. The AAP positions FMR1 repeat testing and selected metabolic studies in a second-tier agnostic pathway but explicitly supports earlier syndrome-directed testing when the phenotype or family history indicates it (AAP, 2025).
This is a clinical decision framework, not an instruction to order every test for every individual. Availability of genetics expertise, laboratory validation, coverage, turnaround time, previous testing, informed preferences, and urgency all shape a defensible sequence. An older algorithm may start with CMA or Fragile X testing; reviewing its publication date and the context of the patient helps explain why modern recommendations differ.
Diagnostic yield: what the numbers actually mean
Diagnostic yield is the proportion of people tested who receive a result considered a molecular explanation under a study's definition. It depends on who was selected for testing, whether structural variants were assessed, sequencing technology, the interpretation standards at the time, and whether investigators included additional medical findings or family data. It is not the probability that a given person has a genetic cause, and it does not measure improvement in day-to-day functioning.
A prominent meta-analysis of 30 studies of neurodevelopmental disorders reported an overall exome diagnostic yield of 36% (95% confidence interval 30%–43%), approximately 31% for more isolated neurodevelopmental presentations, and 53% when associated conditions were present. These were pooled neurodevelopmental cohorts including global developmental delay, intellectual disability, and autism, rather than a pure intellectual-disability sample. The study's later correction did not change the rounded headline yields (Srivastava et al., 2019).
The 2025 AAP report summarizes exome yields of approximately 28%–43% for GDD/ID and estimates around 15%–20% for CMA, noting that genome sequencing can yield more findings in certain comparisons. It also describes higher yields among people with severe impairment, congenital anomalies, or neurological comorbidities. Those estimates should not be added together: the same pathogenic variant can be found by several tests, and the populations and definitions differ (AAP, 2025).
A molecular diagnosis can sometimes be reached in a previously nondiagnostic case years later, because new disorder–gene relationships become established and existing variants are reclassified. For this reason, a one-time negative result is a dated observation. The AAP suggests considering exome or genome reanalysis every one to two years when it remains clinically appropriate and new phenotypic information is available. Reanalysis is distinct from repeating an unchanged assay or paying for an unvalidated commercial interpretation service (AAP, 2025).
Why rates vary by severity and phenotype
People with multiple congenital anomalies, epilepsy, unusual movement disorders, or clearly syndromic findings are often more likely to have a recognizable molecular etiology than people with milder isolated developmental difficulties. Recruitment into specialist clinics also enriches studies for difficult or unusual conditions. Diagnostic-yield studies may underrepresent people with limited access to specialty care, individuals in under-sampled ancestry groups, and adults who have never undergone contemporary testing. Comparisons should specify numerator, denominator, patient selection, and what counts as a confirmed answer, rather than presenting a single yield percentage as universally applicable.
Interpreting a genetic report
Pathogenic and likely pathogenic findings
A pathogenic or likely pathogenic variant is assessed against a specific disorder and its mode of inheritance. Interpretation combines variant-level evidence, established gene–disease validity, clinical phenotype, family segregation, and laboratory quality. A scientifically strong classification does not guarantee that a variant explains every medical or behavioral feature. A person may have more than one genetic diagnosis or additional environmental and clinical contributors. The ACMG/AMP sequence-variant framework provides five standard classes: pathogenic, likely pathogenic, uncertain significance, likely benign, and benign (Richards et al., 2015).
Variants of uncertain significance
A variant of uncertain significance, or VUS, is a finding whose available evidence is insufficient or conflicting for a reliable clinical classification. It is not a diagnosis and should not independently determine irreversible medical, reproductive, or educational decisions. The laboratory may request parental testing, detailed clinical assessment, functional research, or additional data. Subsequent reclassification can move the variant toward pathogenic or benign categories. Clinicians and families should distinguish the variant's certainty from the certainty of the person's developmental needs, which remain real regardless of molecular ambiguity (Richards et al., 2015).
Negative and inconclusive results
A nondiagnostic report means that no adequately supported molecular explanation was found through the selected assay and interpretation at that time. The cause may involve genomic regions or variant types the assay misses, insufficiently understood genes, mosaicism confined to certain tissues, complex inheritance, or contributions that are partly environmental. Some cases remain unexplained despite extensive evaluation. Such a result neither excludes intellectual disability nor removes the need for clinical surveillance, communication support, education, and accommodations.
Secondary and incidental findings
Broad sequencing may identify a medically important variant unrelated to the reason testing was requested. A secondary finding is generally sought deliberately in an agreed set of actionable genes; an incidental finding arises outside the primary diagnostic target. Discussion before testing should address which unrelated findings may be reported, consent and opt-out policies where applicable, the implications for biological relatives, and the age and decision-making capacity of the patient. The ACMG's secondary-findings policy was updated in 2025; specific gene lists and reporting practices require checking the current laboratory and professional standards rather than assuming they are fixed (Miller et al., 2025).
Benefits beyond assigning a diagnostic label
More precise medical care
For a subset of disorders, etiologic diagnosis triggers specific monitoring or interventions, such as cardiac, renal, endocrine, neurological, ophthalmologic, or metabolic surveillance. It can change medication choices, reveal a treatable disease mechanism, support anticipatory guidance, or prevent redundant investigations. The benefit must be assessed disorder by disorder: many established molecular diagnoses currently have no condition-specific disease-modifying treatment, and identifying a cause is not equivalent to curing developmental disability (Manickam et al., 2021; MedlinePlus Genetics, Risks and Limitations).
Ending uncertainty and improving coordination
A credible diagnosis may give families an explanation for a long developmental history, clarify why some medical features co-occur, facilitate access to specialist clinics or peer communities, and make handovers between clinicians more informative. Personal effects differ: relief, grief, altered expectations, worry about other relatives, and disappointment after an inconclusive test can all occur. Counseling should make space for the preferences of the individual who has the disability, not assume every family wants the same depth of testing or the same kinds of findings.
Family planning and recurrence risks
The recurrence risk for a future child depends on the molecular mechanism, not on the general label of intellectual disability. A de novo dominant variant, an inherited dominant variant with variable expression, two recessive variants, an X-linked change, a chromosome rearrangement, and a mosaic finding imply different possibilities. Even apparently de novo results can have residual recurrence risk because of parental germline mosaicism. Genetic professionals can interpret familial testing, reproductive options, and remaining uncertainty without turning probabilistic information into a prediction of an individual's value or quality of life.
Lifespan planning and adult reevaluation
A diagnosis can remain relevant into adulthood, particularly for conditions involving epilepsy, psychiatric comorbidity, organ surveillance, progressive complications, or reproductive counseling. Adults diagnosed with intellectual disability before modern sequencing became available may benefit from updated etiologic evaluation based on present needs and their own informed priorities. The evidence base and insurance policies for adult genomic testing are less uniform than pediatric guidance, and decisions should be individualized instead of mechanically extrapolating every childhood testing algorithm.
Limits of testing and the ethics of interpretation
Clinical validity, analytic validity, and utility
Analytic validity asks whether an assay reliably detects the intended type of DNA change. Clinical validity asks whether the detected change is associated with a particular disease or phenotype. Clinical utility asks whether using that information meaningfully improves decisions, care, or outcomes. These are separate questions. A highly accurate assay can identify a variant whose clinical significance is unknown; a valid diagnosis can clarify prognosis without changing treatment; and a medically actionable finding may require follow-up that the health system struggles to provide. Evaluation of benefits should specify whether outcomes are increased diagnostic yield, changed clinical management, avoided investigations, reproductive information, psychological well-being, or long-term health.
Predicting abilities and severity
Many genetic conditions show variable expressivity: people with the same molecular diagnosis can differ substantially in language, learning, daily living skills, health, and need for assistance. Some genomic changes increase a probability without being fully penetrant. Additional biological factors, personal history, teaching, communication access, family resources, and environmental supports shape functioning. A genetic report cannot translate directly into an IQ score, adaptive score, future independence level, or reliable life-course forecast. Prognosis should use syndrome-specific research when available and the person's observed developmental trajectory, while recognizing the uncertainty in both.
Equity, ancestry, and accessibility
Accurate interpretation relies partly on representative genomic reference data and knowledge of gene–disease relationships. Underrepresentation of some populations can increase uncertainty and the likelihood that a rare benign variant is initially unfamiliar. Genetic services are also unequally distributed by geography, insurance, language, disability access, and specialist availability. Consent materials should accommodate communication needs, sensory differences, literacy, preferred language, and decision-making supports. A result has limited real-world value if the patient cannot access the monitoring or services it implies.
Privacy, relatives, and informed participation
Genomic data may convey information about biological relatives, parentage, reproductive risk, and future health. Consent includes discussion of sample and data storage, reanalysis, potential research use, sharing policies, incidental findings, and the possibility of familial implications. Children, adults with intellectual disability, and supporters require an individualized approach to comprehension and participation. Supported decision-making can help a person express preferences and exercise autonomy. Capacity for a specific decision should be assessed in context; a disability label alone should not be used as a proxy for inability to participate.
The limits of psychological benefit
Some families report relief or a sense of closure after receiving a diagnosis, while others encounter new uncertainty or complex emotions. Clinical studies may measure management changes more consistently than long-term psychological outcomes or meaningful improvements in participation. Claims that genomic diagnosis universally resolves uncertainty, improves mental health, or makes an educational intervention effective exceed what the evidence establishes. Counseling and psychosocial support remain central whether a finding is positive, uncertain, or negative.
Genetic testing and everyday supports
Genomic results can provide a framework for medical surveillance, yet educational assessment and daily supports are selected from the person's actual abilities, communication preferences, environmental barriers, and goals. Intellectual functioning and adaptive behavior should be evaluated with suitable instruments and contextual judgment. A teacher may need to adjust instruction, a speech-language pathologist may introduce augmentative communication, and a family may develop accessible routines regardless of whether sequencing identified a pathogenic variant. Etiologic knowledge and person-centered functional assessment answer complementary questions (AAIDD).
Genetic results can also alert clinicians to associated hearing loss, vision difficulties, sleep disorders, seizure risks, or pain conditions that complicate learning and behavior. When a person's behavior changes, clinicians should investigate potential medical and environmental causes rather than automatically attributing it to intellectual disability or a known syndrome. The value of genetic knowledge is realized through careful interpretation and responsive supports, not through reducing an individual to a molecular label.
A practical decision pathway for patients and families
An appropriate clinical discussion begins with a clear description of the developmental concern and a review of prior diagnostic work. The team explains why testing might identify an etiology, whether recognizable signs suggest a targeted assay, and what broad testing could detect or miss. It then compares the local availability of exome, genome, and microarray testing; considers whether parental samples would help; and identifies specialist consultation or urgent parallel investigations. Informed consent covers possible positive, uncertain, and nondiagnostic results, secondary findings, privacy, family implications, and cost. Results are interpreted together with the clinical picture, and the team records specific actions, unresolved uncertainties, and the conditions under which reanalysis or additional testing would be useful (AAP, 2025).
The strongest practical question to ask after receiving a report is: What exactly changes in care or understanding because of this result? Depending on the finding, the answer may concern condition-specific screening, treatment, specialist referrals, relative testing, recurrence counseling, or simply a more coherent explanation for the developmental history. If no change is available today, the report can still inform future interpretation, provided expectations remain realistic.
Frequently asked questions
Is genetic testing required to diagnose intellectual disability?
No. Intellectual disability is diagnosed through developmental and clinical evidence, intellectual functioning, adaptive behavior, and onset history. Genetic testing investigates an underlying cause and sometimes associated health needs. A nondiagnostic test does not invalidate a clinical diagnosis (AAIDD).
Does every child with unexplained intellectual disability need the same genetic test?
The 2025 AAP guideline supports early broad sequencing in many children with unexplained GDD/ID, but test selection is guided by phenotype, laboratory capabilities, clinical urgency, previous testing, accessibility, and informed preferences. Some characteristic presentations warrant targeted repeat, methylation, chromosome, or metabolic studies first or in parallel (AAP, 2025).
Which is better: exome or genome sequencing?
Genome sequencing can identify more classes of variation and may provide a higher yield in some settings, but performance depends on the platform, analytic pipeline, evidence, and clinical question. Exome sequencing remains valuable and may be more accessible. A clinician should ask what particular assay detects, including copy-number variants, mitochondrial changes, repeats, and mosaicism, and whether follow-up tests are needed.
Can a normal result rule out genetic causes?
No. Negative means the selected test did not establish an explanation using current methods and knowledge. Reanalysis, new gene discoveries, different technologies, additional tissue samples, or targeted biochemical and epigenetic investigations may change the answer later.
Does a pathogenic variant predict the child's IQ or adult independence?
Usually not with individual precision. Genetic diagnoses may inform syndrome-level risks and developmental patterns, but intellectual abilities and adaptive skills require direct assessment, and outcomes depend on multiple biological and social influences. Care plans must remain individualized.
What is a VUS and should treatment change because of it?
A VUS is a variant of uncertain significance. It should not independently direct irreversible clinical decisions. Genetics professionals assess whether new segregation, laboratory, phenotypic, or literature evidence can clarify its meaning (Richards et al., 2015).
When should an old negative genetic result be reconsidered?
Reassessment may be valuable when testing was performed with older technology, when the phenotype changes, when a specific condition becomes suspected, or when genomic interpretation has advanced. The AAP suggests considering reanalysis of nondiagnostic exome or genome data every one to two years in appropriate circumstances (AAP, 2025).
Can adults with intellectual disability undergo genetic evaluation?
Yes. Adults may seek etiologic clarification, medical surveillance, recurrence counseling, or an explanation for co-occurring findings. Consent, accessible communication, clinical utility, insurance availability, and the person's preferences should shape the approach. Pediatric testing guidelines require thoughtful adaptation for adult circumstances.
Scientific conclusions and evidence boundaries
Established evidence supports a substantial genetic contribution to many cases of intellectual disability, the etiologic value of exome and genome sequencing, and the need to interpret findings alongside careful clinical phenotyping. Broad sequencing is now a leading component of pediatric evaluation, while array, repeat, imprinting, biochemical, and specialized technologies remain important for variant classes and syndromes that sequencing can miss. The likelihood of a result varies considerably with the patient population and the test used. These conclusions are supported by major professional guidance and aggregated diagnostic-yield studies (AAP, 2025; Manickam et al., 2021; Srivastava et al., 2019).
Evidence is more limited or heterogeneous for the magnitude of long-term changes in quality of life, learning, family psychological outcomes, and health-service equity following genetic diagnosis. Emerging long-read, methylation, RNA, and AI-assisted interpretation technologies may improve selected diagnostic problems, but validation, implementation, and generalizability must be assessed separately for each application. Continued knowledge development makes reanalysis a rational option without guaranteeing a future answer. The enduring clinical standard is person-centered: genomic findings inform etiologic understanding and health care, while the person's rights, communication, capabilities, and required supports remain central.
Related Articles
How Is Intellectual Disability Diagnosed? Assessment and Diagnostic Criteria — How cognitive and adaptive clinical assessment establishes the disability diagnosis.
Causes of Intellectual Disability: Genetic, Prenatal, and Developmental Factors — The broader etiologic landscape beyond molecular testing.
Global Developmental Delay vs Intellectual Disability: Diagnosis by Age — How developmental stage affects assessment and terminology.
Intellectual Disability vs Specific Learning Disability: Diagnosis and Support — Differentiation between global intellectual-adaptive limitations and specific academic learning disorders.
References
American Academy of Pediatrics. (2025). Rodan, L. H., Stoler, J., Chen, E., and Geleske, T. Genetic evaluation of the child with intellectual disability or global developmental delay: Clinical report. Pediatrics, 156(1), e2025072219. https://doi.org/10.1542/peds.2025-072219.
American Association on Intellectual and Developmental Disabilities. (n.d.). Defining criteria for intellectual disability. https://aaidd.org/intellectual-disability/definition/.
Manickam, K., McClain, M. R., Demmer, L. A., et al. (2021). Exome and genome sequencing for pediatric patients with congenital anomalies or intellectual disability: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG). Genetics in Medicine, 23, 2029–2037. https://doi.org/10.1038/s41436-021-01242-6.
MedlinePlus Genetics. (n.d.). The different types of genetic tests. National Library of Medicine. https://medlineplus.gov/genetics/understanding/testing/types/.
MedlinePlus Genetics. (n.d.). What are the risks and limitations of genetic testing? National Library of Medicine. https://medlineplus.gov/genetics/understanding/testing/riskslimitations/.
MedlinePlus Genetics. (n.d.). What are whole exome sequencing and whole genome sequencing? National Library of Medicine. https://medlineplus.gov/genetics/understanding/testing/sequencing/.
Miller, D. T., Lee, K., Abul-Husn, N. S., et al. (2025). ACMG SF v3.3 list for reporting of secondary findings in clinical exome and genome sequencing: A policy statement of the American College of Medical Genetics and Genomics (ACMG). Genetics in Medicine, 27(8), 101454. https://doi.org/10.1016/j.gim.2025.101454.
Richards, S., Aziz, N., Bale, S., et al. (2015). Standards and guidelines for the interpretation of sequence variants: A joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genetics in Medicine, 17, 405–424. https://doi.org/10.1038/gim.2015.30.
Srivastava, S., Love-Nichols, J. A., Dies, K. A., et al. (2019). Meta-analysis and multidisciplinary consensus statement: Exome sequencing is a first-tier clinical diagnostic test for individuals with neurodevelopmental disorders. Genetics in Medicine, 21, 2413–2421. https://doi.org/10.1038/s41436-019-0554-6.