Investigation of Audiologic Findings in Treated Children with Biotinidase Deficiency: A Retrospective Study

Objective: Biotinidase deficiency (BD) is a metabolic disorder that impairs biotin absorption and can affect the hearing system. In Türkiye, early diagnosis is achieved through newborn screening programs (NSP). Our study aims to present the sociodemographic status and audiologic findings of children with BD admitted to our audiology clinic who received early diagnosis and treatment. Material and Methods: The audiologic findings of patients diagnosed with BD who visited Marmara University Faculty of Medicine, Department of Audiology, between January 2014 and December 2023 were retrospectively analyzed. The study included 24 participants (12 female, 12 male) aged between 4-24 months. Sociodemographic information, newborn hearing screening results, acoustic immittancemetry, otoacoustic emissions (OAE), and auditory brainstem responses (ABR) findings were evaluated. Results: All participants were diagnosed with BD during NSP, and all had passed newborn hearing screening. In the ABR evaluation using click stimuli, the absolute latency values of waves I, III, and V, as well as the interwave latencies (I-III, III-V, I-V), were normal for their age. Threshold assessments with chirp stimuli showed wave V at 20 dB nHL in all participants. Acoustic immittancemetry and OAE findings were normal. As a result of all evaluations, all participants had normal hearing. Consanguine marriage was reported in the parents of 5 (20.8%) participants. Conclusion: Our findings support that hearing loss can be prevented with NSP in children with BD who received early diagnosis and treatment. National NSP is important in Türkiye.