Clinical characteristics of a Japanese patient with Bardet-Biedl syndrome caused by BBS10 mutations
Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder characterized by retinal dystrophy, renal dysfunction, central obesity, mental impairment, polydactyly, and hypogonadism. Only limited information on BBS is available from Japanese patients. In addition, there are currently no reports of Japanese patients with BBS caused by BBS10 mutations. The purpose of this study was to present the characteristics of a Japanese patient with BBS caused by BBS10 mutations.
Patient and methods
The patient was a 22-year-old Japanese woman. Comprehensive ophthalmic examinations, including visual acuity measurements, perimetry, electroretinography (ERG), fundus autofluorescence imaging, and optical coherence tomography, were performed. Trio-based whole-exome sequencing was performed to identify potential pathogenic mutations, confirmed by Sanger sequencing.
The patient showed neither renal malformation nor dysfunction, and visual impairment seemed to be relatively mild for BBS. The fundus examination revealed diffuse retinal degeneration without pigmentary deposits, and ERG scans showed undetectable responses. She had a history of surgically corrected polydactyly, and displayed symptoms of obesity. There was also a menstrual irregularity that could require progestin administration. Genetic analysis revealed compound heterozygous BBS10 mutations in the patient: a novel missense mutation c.98G>A [p.(G33E)], and a novel nonsense mutation c.2125A>T [p.(R709*)].
To our knowledge, this is the first description of a Japanese patient with BBS caused by BBS10 mutations. The clinical characteristics of our patient were mild, as neither renal impairment nor legal blindness was observed. Early diagnosis would play a role in providing counseling, and in some cases, therapeutic interventions for BBS patients.
KeywordsBardet-Biedl syndrome BBS10 gene retinal dystrophy systemic findings
The authors would like to thank Editage (https://www.editage.jp/) for English language editing. This work was supported by a Grant from the Initiative on Rare and Undiagnosed Diseases for Adults (no. 16ek0109151h0002) from the Japan Agency for Medical Research and Development (AMED), and the Japan Society for the Promotion of Science Grant-in-Aid for Scientific Research (no. 26462659 awarded to Y. H. and no. 16K11284 awarded to K. H.).
Conflicts of interest
K. Kurata, None; K. Hosono, None; A. Hikoya, None; A. Kato, None; H. Saitsu, None; S. Minoshima, None; T. Ogata, None; Y. Hotta, None.
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