Phenotype\u2013genotype correlation in patients with typical and atypical branchio-oto-renal syndrome

Masatsugu Masuda,Sawako Masuda,Sayaka Katsunuma,Kiyomitsu Nara,Kaoru Ogawa,Atsuko Nakano,Yasuhide Okamoto,Tomoko Sugiuchi,Ayako Kanno,Hideki Mutai,Tatsuo Matsunaga,Noriko Morimoto,Naoya Morisada,Kazumoto Iijima

doi:10.1038/s41598-022-04885-w

Abstract

Some patients have an atypical form of branchio-oto-renal (BOR) syndrome, which does not satisfy the diagnostic criteria, despite carrying a pathogenic variant (P variant) or a likely pathogenic variant (LP variant) of a causative gene. P/LP variants phenotypic indices have yet to be determined in patients with typical and atypical BOR syndrome. We hypothesized that determining phenotypic and genetic differences between patients with typical and atypical BOR syndrome could inform such indices. Subjects were selected from among patients who underwent genetic testing to identify the cause of hearing loss. Patients were considered atypical when they had two major BOR diagnostic criteria, or two major criteria and one minor criterion; 22 typical and 16 atypical patients from 35 families were included. Genetic analysis of EYA1, SIX1, and SIX5 was conducted by direct sequencing and multiplex ligation-dependent probe amplification. EYA1 P/LP variants were detected in 25% and 86% of atypical and typical patients, respectively. Four EYA1 P/LP variants were novel. Branchial anomaly, inner ear anomaly, and mixed hearing loss were correlated with P/LP variants. Development of refined diagnostic criteria and phenotypic indices for atypical BOR syndrome will assist in effective detection of patients with P/LP variants among those with suspected BOR syndrome.

Highlights

Some patients have an atypical form of branchio-oto-renal (BOR) syndrome, which does not satisfy the diagnostic criteria, despite carrying a pathogenic variant (P variant) or a likely pathogenic variant (LP variant) of a causative gene
SIX1 interacts with EYA1 and participates in the development of the eye, inner ear, and kidney[11], while SIX5 protein binds to EYA1 protein and activates gene transcription[4]
Our results suggest that refining the diagnostic criteria for atypical BOR syndrome may assist in effective detection of patients with P/LP variants, even for atypical patients

Summary

Introduction

Some patients have an atypical form of branchio-oto-renal (BOR) syndrome, which does not satisfy the diagnostic criteria, despite carrying a pathogenic variant (P variant) or a likely pathogenic variant (LP variant) of a causative gene. P/LP variants phenotypic indices have yet to be determined in patients with typical and atypical BOR syndrome. We hypothesized that determining phenotypic and genetic differences between patients with typical and atypical BOR syndrome could inform such indices. Development of refined diagnostic criteria and phenotypic indices for atypical BOR syndrome will assist in effective detection of patients with P/LP variants among those with suspected BOR syndrome. There are some reports of patients with atypical BOR syndrome, which does not satisfy the clinical criteria for typical BOR syndrome, despite carrying EYA1 or SIX1 mutations[12,15,19]. We refer to patients with typical or atypical BOR syndrome as typical or atypical patients, respectively

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Results

Conclusion