Deletion of a genetic region at chromosome 16p12.1 is found in some children with intellectual disability/developmental delay (ID/DD) and congenital malformations, according to a study published online this week in Nature Genetics. These results support a two-hit model in which a deletion at 16p12.1 acts as a risk factor for ID/DD and a secondary mutation results in more severe clinical problems.
Developmental delays, such as failing to sit, walk, and talk, at the average age, is a common symptom of mental retardation, cerebral palsy, autism spectrum disorder, Down syndrome, as well as other disorders.
Evan Eichler and colleagues analysed the genomes of over 21,000 children with intellectual disability/developmental delay. The scientists find that in 42 of the children, there is a deletion at chromosome 16p12.1, compared to 8 of 14,839 controls. Children carrying both the 16p12.1 deletion and an additional chromosomal abnormality exhibited more severe symptoms than children carrying only the additional mutation.