Detection of Epidermal Thickening in GJB2 Carriers with Epidermal US1

Purpose: To measure epidermal thickness by using skin ultrasonography (US) in a series of healthy control subjects and obligate carriers for the worldwide most frequent form of congenital hearing loss owing to the mutated alleles of the connexin 26 gene ( GJB2 ). Materials and Methods: The patent for the protocol, coupled with a new sonographic probe specifically designed to analyze epidermal thickness and a dedicated algorithm to classify individuals in groups, is pending. Institutional ethics committee approval and patient consent were obtained. After a preliminary study in 23 subjects aimed to define the best body site and instrument and protocol for US, a total of 303 individuals (237 healthy subjects, 51 carriers, and 15 homozygotes) were tested at midline forehead by using a linear large-band probe with a frequency ranging from 6 to 15 MHz to determine epidermal thickness. Variance and linear regression analyses were performed. Regression coefficients were then used to obtain measurements of thickness corrected for age and sex. Results: GJB2 obligate carriers had a significant increase in epidermal thickness compared with control subjects. GJB2 status explains about 50.0% of this variability, whereas an additional 25.0% is explained by sex and age. Results led to the development of a possible screening protocol with a 98.0% sensitivity and 92.8% specificity in subjects aged 20 80 years, with a likelihood ratio of a positive test of 14:1. Even better results (100% sensitivity and 98.9% specificity) were obtained in an analysis of people of only reproductive age. Conclusion: Epidermal thickening in the white population owing to GJB2 carrier status can be detected by using US. This measurement could provide a simple, noninvasive, rapid, and sensitive test for carrier screening. © RSNA, 2009