Genetic developmental disability diagnosed in adulthood: a case report

Developmental disabilities (DD) are an umbrella term for conditions associated with functional impairments in physical, learning, language, or behavior areas. Intellectual disability (ID) is a type of developmental disability that results in delays in cognitive or intellectual functioning, such as reasoning, learning, and problem-solving, and adaptive behaviors including social and practical life skills. DD can be due to a variety of factors, ranging from environmental exposures to genetic mutations, and studies suggest that up to 40% of DDs may be caused by genetic issues.

In this case study, we present an 18-year-old internationally adopted female Chinese American patient with a known history of developmental delay, intellectual disability, strabismus, and a congenital heart defect who had not been tested for genetic causes of her delay prior to presentation. When evaluated with chromosomal microarray, the patient demonstrated a deletion on the short arm of chromosome 5, an area associated with Cri-du-chat syndrome. This chromosomal deletion was a likely explanation for her history of developmental delays, intellectual disability, and congenital heart defect, in addition to her history of institutionalization and the trauma of multiple caregiver transitions in early childhood. The patient was referred for further evaluation by a geneticist and genetic counselor.

This case highlights that the underlying cause of developmental delay is often multifactorial, and underscores the importance of a full medical evaluation, including genetic testing, for children with intellectual disability. Using this approach, healthcare professionals can identify potential diagnoses and provide more targeted resources to families.