What comes next after a GDD/ID diagnosis
Identifying global developmental delay or intellectual disability is an important first step, but it doesn’t always clarify what’s driving a child’s challenges.
Why the underlying cause isn’t always obvious
- GDD/ID can have many possible causes, with up to 50% attributed to an underlying genetic disorder.1
A clearer path to answers
- ~85% of known disease-related variants are found within the Exome.2 Exome (+CMA) evaluates ~20,000 disease-causing genes at once, offering a more thorough approach than traditional testing methods, with findings delivered in clear, concise reports you can use to provide answers to families’ biggest questions.
When to consider exome sequencing
Global Developmental Delay (GDD)
Global developmental delay is identified in children under 5 years of age, through developmental surveillance and screening during pediatric visits or well-child checkups. GDD can often serve as an initial clinical diagnosis and typically prompts further diagnostic evaluation.
GDD is defined as the failure to meet expected developmental milestones across two or more developmental domains:3
- Speech and language
- Gross and/or fine motor skills
- Cognitive development
- Social functioning
- Activities of daily living
Intellectual Disability (ID)
Usually diagnosed in children over the age of 5, intellectual disability may follow an earlier diagnosis of global developmental delay when deficits in intellectual and adaptive functioning persist.
ID is defined as:3
- Significant limitations both in intellectual functioning and in adaptive behavior with onset during the developmental period
Featured tests
Genetic testing solutions
Exome sequencing
Often the first, most effective step when a genetic cause is suspected. That’s because most known disease-causing variants are found within the exome.
Genome sequencing
The most complete view of the genome, providing deeper insights beyond the exome when a broader search is needed.
What earlier answers can change
Patients with a rare disease often face a prolonged diagnostic odyssey: an accurate diagnosis takes an average of 5 years;4 two-thirds (62%) of patients see more than four specialists;5 and patients can undergo 16 or more medical tests6. Earlier answers can influence care well beyond explaining delays—shortening the diagnostic odyssey and helping families move forward with greater clarity.
A genetic diagnosis can help:
- Guide care coordination and referrals, clarifying when subspecialty involvement may be appropriate7
- Inform anticipatory guidance and clinical monitoring for associated medical concerns7
- Support access to services and resources, including therapies and condition-specific support7
- Provide families navigating uncertainty with clear answers that help them move from searching for answers to understanding what comes next
Exome/Genome sequencing are recommended as first-line tests by leading medical societies
- The American Academy of Pediatrics (AAP) recommends ordering exome and genome as first-line tests for children with global developmental delay and intellectual disability.8
- The National Society of Genetic Counselors (NSGC) recommends genome or exome as a first-line test for all individuals with unexplained epilepsy and this guideline is endorsed by the American Epilepsy Society (AES).9
- The American College of Medical Genetics and Genomics (ACMG) recommends genome or exome as a first-line test for developmental delay, intellectual disability, and congenital anomalies.10
- The International Precision Child Health Partnership (IPCHiP) recommends genome or exome as a first-line test for NICU patients with unexplained hypotonia.11
Real families, real answers
Families across the country have found clarity with GeneDx—ending years of uncertainty and opening doors to better care.
Meet Carlotta & Andrea
"Carlotta was undiagnosed for 18 months until we were finally able to access whole exome sequencing to identify the underlying cause of her issues: PIGN-CDG. While it doesn’t necessarily change her immediate prognosis, it does change what the long-term prognosis could be. We wouldn’t have options if we didn’t understand what exactly it was that we were dealing with.”—Andrea
Helpful resources
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