Clinical Findings and BTD Gene Molecular Analysis Results of Patients Presenting with Suspicion of Biotinidase Deficiency

Aim: Biotinidase deficiency is an autosomal recessive disease, also known as late-onset biotin-sensitive multiple carboxylase deficiency caused by pathogenic mutations in the biotinidase (BTD) gene responsible for the production of biotinidase. In this study, we aimed to present the clinical findings and BTD gene molecular analysis results in the light of the literature. Material and Methods: Nine patients who were positive in heel blood screening and cases compatible with neurological, sensory, metabolic, respiration and skin findings of biotinidase deficiency were included in the study. For the isolation of genomic DNA from the participants included in the study, 2 cc of peripheral blood was taken into Ethylene Diamine Tetra Acetic Acid (EDTA) tubes and their genomic DNA was isolated and sequence analysis of the BTD gene was performed. Results: According to the all exon sequence analysis results of the BTD gene, homozygous c.1368A>C/p.Gln456His mutation was detected in 1 patient; heterozygous c.1368A>C/p.Gln456His mutation was detected in 1 patient; combined heterozygous c.1330G>C/p.Asp444His and c.511G>A/p.Ala171Thr mutations were detected in 1 patient, combined heterozygous c.1336G>C/p.Asp446His and c.511G>A/p.Ala171Thr were detected in 1 patient, and c.557G>A/p.Cys186Tyr mutation was detected in 1 patient. No mutation was detected in 4 patients. Conclusion: Early diagnosis and treatment are very important for eliminating the problems experienced by patients with BTD disorder and for preventing complications that may occur in case of delay. It is important that informing the patient and family members about the prenatal diagnosis or preimplantation genetic diagnosis method for autosomal recessive inherited disease by giving genetic counseling