Micro-duplications of 1q32.1 associated with neurodevelopmental delay

Distal partial trisomies involving the region 1q32 have been associated with dysmorphic features and developmental delay [1], [2], [3], [4], [5], [6], [7], [8], [9], [10] and [11]. To further define the critical region for developmental delay and to investigate the genotype–phenotype association of 1q trisomy syndrome, we report two patients with much smaller (3 Mb and 3.5 Mb in size) trisomic regions on 1q32.1. The two micro-duplications largely overlap and both patients exhibited cognitive and motor delays. Case 1 is a 5-year-old boy with global developmental delay, behavioral problems, pervasive developmental disorder not otherwise specified (PDD-NOS), staring spells, headaches, and paresthesias. Case 2 is a 14-year-old girl with seizures, cognitive and motor difficulties, and minor dysmorphic features. These two cases suggest that 1q32.1 region on distal arm of 1q and genes involved are critical to cognitive and motor development in a gene dosage sensitive manner and that other neurological features are variable within this syndrome.

► Large partial trisomies of chromosome 1q are associated with developmental delays.
► We describe two probands with 1q32 micro-duplications and developmental delays.
► We propose possible candidate genes in the region including KDM5B, NAV1, and KIF21B.