Identification of Novel Gene Variations Associated with Bardet-Biedl Syndrome-12

Abstract

Background: This study aimed to identify potential pathogenic gene variations associated with Bardet-Biedl syndrome type 12 (BBS12) in a Chinese family. Case Description: Single nucleotide polymorphism microarray (SNP-Array) and whole exome sequencing were performed to identify pathogenic gene variations associated with BBS12, which was phenotypically characterised with antenatal ultrasonography and post-natal examination. Antenatal SNP-Array analysis revealed a 107.8 Kb deletion in the 4q27 segment of chromosome 4. An initial whole exome sequencing detected a homozygous mutation on the BBS12 gene in the family: there was one de novo mutation inherited from the mother while another gene mutation was from the father. After five years follow-up, whole exome sequencing identified a heterozygous BBS12 mutation, c.337_339del (p.V113del) inherited from the father, accompanied with a heterozygous deletion of chr4: 123653861–123748536 inherited from the mother. Conclusions: BBS is a rare autosomal recessive disorder, usually caused by a pathogenic homozygous mutation or compound heterozygous mutation in the BBS gene. This article reports a novel case of BBS12 that resulted from both a heterozygous mutation and heterozygous deletion for the first time.