Auditory phenotype of Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation and intellectual disability syndrome resulting from variants in DHCR7. Auditory characteristics of persons with SLOS have been described in limited case reports but have not been systematically evaluated. The objective of this study is to describe the auditory phenotype in SLOS. Age- and ability-appropriate hearing evaluations were conducted on 32 patients with SLOS. A subset of 21 had auditory brainstem response testing, from which an auditory neural phenotype is described. Peripheral or retrocochlear auditory dysfunction was observed in at least one ear of 65.6% (21) of the patients in our SLOS cohort. The audiometric phenotype was heterogeneous and included conductive, mixed, and sensorineural hearing loss. The most common presentation was a slight to mild conductive hearing loss, although profound sensorineural hearing loss was also observed. Abnormal auditory brainstem responses indicative of retrocochlear dysfunction were identified in 21.9% of the patients. Many were difficult to test behaviorally and required objective assessment methods to estimate hearing sensitivity. Individuals with SLOS are likely to have hearing loss that may impact communication, including speech and language development. Routine audiologic surveillance should be conducted to ensure prompt management of hearing loss.