1p21.3 Microdeletion Syndrome

1p21.3 microdeletion syndrome is an extremely rare chromosomal anomaly characterized by severe speech and language delay, intellectual deficiency, autism spectrum disorder(see this term).

Epidemiology

Less than 10 cases have been reported to date.

Clinical description

1p21.3 microdeletion syndrome is characterized by severe speech and language delay, a borderline-mild to mild-moderate intellectual deficiency, autism spectrum disorder (see this term) features, and minor dysmorphic facial features such as long ears, deep set eyes, a broad nasal tip and a thick lower lip. Affected individuals have normal gross motor development without major abnormalities, they are often very shy and friendly with a tendency to overeat.

Etiology

1p21.3 microdeletion syndrome is caused by a hemizygous interstitial microdeletion on the short arm of chromosome 1, occurring mostly de novo, that implicates DPYD (dihydropyrimidine dehydrogenase) and MIR137 genes associated with miRNA pathways.