Mutation spectrum and genotype-phenotype correlation of hearing loss patients caused by SLC26A4 mutations in the Japanese: a large cohort study.

[pendred syndrome]

Mutations in SLC 26 A 4 cause a broad phenotypic spectrum , from typical Pendred syndrome to nonsyndromic hearing loss associated with enlarged vestibular aqueduct . Identification of these mutations is important for accurate diagnosis , proper medical management and appropriate genetic counseling and requires updated information regarding spectrum , clinical characteristics and genotype-phenotype correlations , based on a large cohort . In 100 patients with bilateral enlarged vestibular aqueduct among 1511 Japanese hearing loss probands registered in our gene bank , goiter data were available for 79 , of whom 15 had Pendred syndrome and 64 had nonsyndromic hearing loss . We clarified the mutation spectrum for the SLC 26 A 4 mutations and also summarized hearing levels , progression , fluctuation and existence of genotype-phenotype correlation . SLC 26 A 4 mutations were identified in 82 of the 100 patients (82 .0 %). Of the Pendred syndrome patients , 93 % (14 /15 ) were carriers , as were 77 % (49 /64 ) of the nonsyndromic hearing loss patients . Clinical characteristics of patients with SLC 26 A 4 mutations were congenital , fluctuating and progressive hearing loss usually associated with vertigo and /or goiter . We found no genotype-phenotype correlations , indicating that , unlike in the case of GJB 2 mutations , the phenotype can not be predicted from the genotype . Our mutation analysis confirmed the importance of mutations in the SLC 26 A 4 gene among hearing loss patients with enlarged vestibular aqueduct and revealed the mutation spectrum , essential information when performing genetic testing .

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Diseases presenting "appropriate genetic counseling and requires updated information regarding spectrum" symptom

pendred syndrome

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