A Homozygous Missense Variant in <i>HSD17B4</i> Identified in Two Different Families

Background: Perrault syndrome is an inherited disorder with clinical findings that differ according to sex. It is characterized by a variable age of onset and sensorineural hearing loss in both sexes, as well as ovarian dysfunction in females with a 46,XX karyotype. Although it is a rare autosomal recessive syndrome, with approximately 100 affected individuals reported in the literature, it shows both genotypic and phenotypic variations. Mutations in the HSD17B4 gene have been identified as one of the genetic causes of Perrault syndrome. Case Presentation: A female case and a male case from two different unrelated families with a new variant in the HSD17B4 gene, which were not previously described in the literature and were accompanied by hearing loss, skeletal anomalies, and neurological symptoms, were presented. Conclusion: We defined Perrault syndrome cases in Turkey caused by a novel mutation in HSD17B4. Whole-exome sequencing is a useful diagnostic technique with varying clinical results due to genetic and phenotypic heterogeneity.