Biotinidase deficiency and its impact on the auditory system in Iranian children

Abstract

Background and Aim: Biotinidase deficiency (BTD) is a rare autosomal recessive abnormality of biotin metabolism. If left untreated, it may lead to auditory symptoms. In this study, we examined the possible relationship between BTD and hearing impairment among Iranian children. Methods: This descriptive cross-sectional study was performed on 9 children (8 boys, 1 girl) with BTD, who referred to Imam Hossein Hos­pital in Isfahan City, Iran, in 2018. After coll­ecting their demographic data, including age, gender, weight, height, and history of diseases, we performed routine otolaryngologic and neu­rologic examination, audiological examinations, including otoscopic, acoustic immittance mea­surements, and auditory brainstem response (ABR). We recorded cochlear microphonic res­ults in most cases, too. Results: The subjects’ mean ± SD age of BTD diagnosis was 4.33 ± 5.36 months. Of all par­ticipants, 11.1% had a positive family history of the disease, and 66.7% of families had the first-degree consanguineous marriage. About 44.5% of participants had a normal hearing; 22.2% had moderate sensorineural hearing loss, and 33.3% showed no response to ABR test. All subjects showed normal acoustic immittance results. However, children with profound hearing loss showed bilateral absence of acoustic reflexes. Conclusion: BTD has a high impact on a chi­ld’s hearing system. The high prevalence of hearing loss among BTD patients suggests that parents of BTD children (diagnosed at birth) should pay special attention to auditory scree­ning and follow-up programs, as early diagnosis is important for preventing hearing loss. Also, families with first-degree of consanguineous marriages should consider genetic counseling before having children.   Keywords: Biotinidase deficiency; hearing impairment; children