Intellectual and Developmental Disabilities (IDDs) are a group of disorders that can impact cognitive function and physical or neurological development across the lifespan. These conditions can make it harder for people to learn, communicate, solve problems, and perform self-care activities like dressing and eating. Many IDDs are diagnosed in early childhood. However, some IDD symptoms may become more noticeable later in life, and undiagnosed adults may struggle with daily living, social skills, or employment as they age.
Diagnosing IDD Using Genetic Evaluations
Up to 50% of IDDs have genetic causes, and the American Academy of Pediatrics recommends genome and exome sequencing as first-tier tests for children with global developmental delay or intellectual disability. However, adults face disparities in access to genetic evaluation and IDD care. Genetic testing remains underused in adults with IDD, despite high diagnostic yields and the increased affordability and access to whole exome sequencing (WES) and whole genome sequencing (WGS) technology.
Benefits of a Genetic IDD Diagnosis
Identifying a genetic cause for IDD can provide many benefits to pediatric and adult patients.
Predict Outcomes: Understand how the condition may develop and change over time.
Immediate Management: Tailor therapeutic approaches to a patient’s genetic diagnosis and profile to maximize efficacy and minimize adverse effects.
Preventive Care and Surveillance: Enable early interventions with targeted monitoring and proactive risk and symptom management for disorder-related complications.
Family Planning: Assess the chance of a condition occurring in children or other relatives.
Support: Link families to IDD support groups, clinical studies, specialists, and other resources, potentially including disability income and services.
Case Insights: Comprehensive Genetic Testing in Adults with IDD
At the 2025 ACMG (American College of Medical Genetics and Genomics) meeting, SequenceMD presented research on the diagnostic yield and clinical utility of genetic testing in adults with IDD. Of 69 adults referred to SequenceMD between 2022 and 2024, our genetic evaluations had a diagnostic yield of 37.7%, with WES/WGS outperforming gene panels (73.1% vs. 23.1%).
Clinical outcomes of testing adult IDD patients included therapeutic interventions and medication changes (27.5%), preventive care (34.8%), and long-term planning (37.7%). These findings showcase the value of genomic testing for optimizing adult IDD management and advocate for including WES and WGS as foundational diagnostic tools for adults with IDD.
To learn more about this research, click on SequenceMD poster graphic.
To listen to an audio tour of the poster, which was provided by Rebeca Venezia, MS, CGC of SequenceMD, who collaborated on the research with Patrick Long, MD, click the play button.
Please refer to the following documents for more information about the research: patient ICD-10 codes, references and patient location zip codes. The map indicates patients in rural areas where care may be scarce sometimes, but SequenceMD provided help with a diagnosis and/or management care.
Our Patient-Centric Approach
SequenceMD begins every genetic evaluation with the patient, not the referral. Rather than testing based on a single suspected diagnosis, each evaluation combines a full clinical history, cross-system findings, and family risk assessment.
We holistically evaluate each patient, considering genetic, environmental, and familial factors. Our testing indications expand as any additional risks are found (like family history of cancer prompting hereditary cancer testing). Through secondary and complementary testing (such as pharmacogenomics, carrier screening, and polygenic risk scoring), we bring to light vital care considerations and build a complete genomic health profile for every patient.
Collaborative, Personalized Care
Our expert clinical geneticists provide detailed, evidence-based recommendations to primary care and referring providers, translating genomic findings into actionable clinical guidance. After an IDD diagnosis, we work with care teams to:
- Review the condition’s natural history, clinical presentation, and medical management
- Discuss targeted treatment options, specialty consultations, and monitoring
- Guide family counseling and service coordination
- Deliver continuing patient care with annual follow-ups
- Reanalyze genetic data and results in light of new breakthroughs
