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Prospective parents often wonder if neurodevelopmental disorders (like autism, ADHD, or intellectual disabilities) are congenital, meaning present from birth. In many cases, the answer is yes – neurodevelopmental disorders frequently have congenital origins rooted in genetics or prenatal factors. However, the relationship is complex. Understanding how congenital conditions and neurodevelopmental disorders overlap can help parents make informed decisions, especially with advanced embryo genetic screening options like Orchid’s whole genome preimplantation genetic testing (PGT).

Congenital Conditions vs. Neurodevelopmental Disorders

Congenital conditions are those present at birth. These include structural birth defects (e.g. heart defects, cleft palate) and genetic syndromes. Neurodevelopmental disorders, on the other hand, affect the development of the brain and nervous system, influencing cognition, behavior, or motor skills as a child grows. While neurodevelopmental disorders (NDDs) like autism spectrum disorder or intellectual disability may not be obvious at birth, many stem from underlying congenital factors. For example, Down syndrome – caused by an extra chromosome present from conception – leads to intellectual disability, bridging a congenital genetic condition and a neurodevelopmental outcome. Likewise, a chromosomal deletion such as in Wolf-Hirschhorn syndrome is present from birth and causes developmental delay and intellectual disability (along with physical birth defects) (Is there genetic testing for Intellectual Disability and Developmental Delay?). In short, not all NDDs come with visible birth defects, but many have genetic roots present at birth, classifying them as congenital in origin.

Genetic Origins and Overlap

Genetics play a crucial role in both congenital anomalies and neurodevelopmental disorders. Studies indicate that approximately 15–20% of children with neurodevelopmental disorders have chromosomal abnormalities – extra or missing pieces of DNA. (Wolf-Hirschhorn syndrome, mentioned above, is one such example.) Another significant subset – roughly 10% – have a single-gene mutation (monogenic cause) underlying their condition. These genetic issues are present from the start of life, even if the neurodevelopmental disorder is diagnosed later in infancy or childhood. In other words, many neurodevelopmental disorders are congenital in a genetic sense.

It’s also important to note that some genetic causes arise spontaneously. A large proportion of neurodevelopmental disorders result from new mutations not inherited from either parent (called de novo mutations). For example, over 99% of cases of Rett syndrome (a severe neurodevelopmental disorder) are caused by a random, non-inherited genetic variant in the embryo (Is there genetic testing for Intellectual Disability and Developmental Delay?). Families with no history of a disorder can still have a child born with it due to these chance genetic changes. Environmental factors (such as prenatal exposures or birth complications) can also contribute to neurodevelopmental issues, but those would be congenital influences as well (since they occur before or at birth). Understanding these genetic and congenital underpinnings is key for parents looking to assess and reduce the risks of neurodevelopmental disorders in their children. Discussing these concerns with clinicians and genetic counselors can often identify families at risk and allow further testing.