Chromosome 3q29 Duplication Syndrome

A number sign (#) is used with this entry because the phenotype is caused by a microduplication of chromosome 3q29 (chr3: 197.1-198.9 Mb, NCBI35).

See also 609425 for a chromosome 3q29 deletion syndrome.

Clinical Features

Lisi et al. (2008) reported a 3-generation family in which 5 members had mild to moderate mental retardation and minor dysmorphic features associated with an interstitial microduplication of chromosome 3q29. Clinical features included microcephaly, round face, bulbous nose, short or downslanting palpebral fissures, excessive hand creases, and pes planus.

Cytogenetics

By FISH analysis, array comparative genomic hybridization (CGH), and SNP genotype analysis Lisi et al. (2008) found the microduplication of chromosome 3q29 was between 1.61 and 1.76 Mb in size, with the breakpoints occurring between 2 nearly identical low-copy repeat sequences. The proximal break occurred between SNP rs11926771 (base position 197,145,041) and SNP rs6797622 (base position 197,223,225), while the distal breakpoint occurred between SNP rs11922324 (base position 198,832,486) and SNP rs6583248 (base position 198,910,079) (NCBI35).