Prevalence and associated factors of hearing loss in 70 Iranian patients with mucopolysaccharidosis

Mucopolysaccharidosis (MPS) is a rare multisystem genetic disorder caused by lysosomal enzyme deficiencies, leading to accumulation of glycosaminoglycans and progressive involvement of multiple organs. Hearing loss is a common but under-recognized manifestation. Hearing loss in MPS patients does not present as a uniform pattern and may include conductive, sensorineural, or mixed components. From a clinical perspective, distinguishing the type of hearing loss and ensuring early diagnosis are important for timely intervention because hearing loss may negatively affect speech and communication abilities in children with MPS, underscoring the importance of early and comprehensive audiological assessment. This study aimed to evaluate the prevalence and associated factors of hearing loss in Iranian patients with mucopolysaccharidosis. In this descriptive cross-sectional epidemiological study, 71 children with MPS referred to two tertiary referral Children’s Hospitals in Tehran province, Iran entered study. Audiological assessments included pure-tone audiometry (PTA), otoacoustic emission (OAE), and auditory brainstem response (ABR) and tympanometry were performed for 70 patients. Hearing loss was defined as PTA > 25 dB HL in at least one ear. Demographic, clinical, and treatment related variables were analyzed. Among the patients, 42 patients were boys (59.2%). The mean age of the patients was 11.97 ± 6.38 years. Hearing loss was identified in 45 patients (64.29%), while 25 (35.71%) had normal hearing. The highest hearing loss rate was observed in MPS II (Hunter :100%), followed by MPS IIIA (Sanfilippo:66.7%) and MPS I (Hurler:63.6%). No statistically significant association was found between hearing status and duration of enzyme replacement therapy (ERT) ( P = 0.81), bone marrow transplantation (BMT) ( P = 0.21), or treatment modality ( P = 0.9). Hearing loss is highly prevalent among patients with MPS and appears to be independent of current therapeutic interventions. Regular audiological screening and early rehabilitation is essential to improve communication outcomes and quality of life in this population.