Clinical and genetic features of hearing loss in facioscapulohumeral muscular dystrophy

Abstract

Objective: To describe the hearing loss in facioscapulohumeral muscular dystrophy (FSHD) and examine the relationship to genotype.

Methods: Medical records of all individuals with FSHD seen at the University of Iowa neuromuscular clinic between July 2006 and July 2012 (n = 59) were reviewed. Eleven had significant hearing loss and no non-FSHD cause. All available audiology records for these individuals were analyzed. The relationship between the FSHD mutation (EcoRI/BlnI fragment size) and hearing loss was evaluated using a logistic regression analysis.

Results: In patients with hearing loss, recalled age at onset of facial weakness ranged from birth to 5 years and shoulder weakness was 3 to 15 years. The age at diagnosis of hearing loss ranged from birth to 7 years. Only 2 were identified by newborn hearing screen. Most audiograms demonstrated a bilateral, sloping, high-frequency sensorineural hearing loss. Of the 4 patients with more than 5 years of data, 3 had progression of hearing loss. Logistic regression showed statistically significant negative association between the presence of hearing loss and EcoRI/BlnI fragment size (p = 0.0207).

Conclusions: FSHD with a small EcoRI/BlnI fragment is associated with a bilateral, progressive, sloping, high-frequency hearing loss with onset in childhood. Patients with FSHD and small EcoRI/BlnI fragment sizes should have hearing screened, even if the child passed newborn hearing screening.

Figure 1. Pure tone audiometry data from participants with more than 5 years of data

Hearing loss was progressive in 3 of 4 patients for whom we had more than 5 years of audiometry data. Data are from the following participants: (A) patient 1, (B) patient 4, (C) patient 7, and (D) patient 11. Only right ear data are shown, but results are representative of left ear as well except for patient 7, whose left ear showed mild to moderate sloping hearing loss. Age at audiometry data in years is shown in the key on the right of each chart.

Figure 2. Probability of hearing loss as predicted by EcoRI/BlnI fragment size from simple logistic regression analysis

Association between small EcoRI/BlnI fragment size and higher probability of hearing loss was statistically significant (p = 0.0207). The black line represents the logistic regression curve predicted by our cohort. The red lines represent 95% confidence bands.