A 17q24.3 duplication identified in a large Chinese family with brachydactyly-anonychia

Brachydactyly (BD) is a rare autosomal dominant inherited disease characterized by shortness of the fingers and/or toes, which has been classified into the subtypes A-E. However, the exact cause and mechanism of BD remain to be illuminated. Here, we aim to reveal the clinical and genetic characteristics of a subtype of BD, brachydactyly-anonychia.

In this study, a large Chinese family with three members affected by brachydactyly-anonychia was investigated. Both whole-exome sequencing and microarray-based comparative genomic hybridization (CGH) were performed on this family and the results of copy number variation (CNV) were verified by quantitative real-time PCR (qPCR).

All the affected individuals showed short fingers and toes as well as missing nails; and the absence of middle phalanges in figure II-V of the upper and lower extremities was observed by X-ray examination. A duplication involving in the region of 17q24.3 was detected by CGH. The results of qPCR also represented this duplication in 17q24.3 in all the patients.

In summary, our findings suggest that 17q24.3 duplication is the genetic cause of brachydactyly-anonychia in this family, which support the prior report that brachydactyly-anonychia is associated with 17q24.3 duplication, and further indicates the pathogenic correlation between BD and CNVs.