[Estimation of vitamin A (Retinol) and retinol-binding protein (RBP) in serum of hearing impaired children (author's transl)].

Retinol and Retinol-binding protein are estimated in the plasma of 91 children with hearing impairments of different etiology and 35 normal children of similar age. The concentrations of Retinol and Retinol-binding protein are age-dependent but in a given age class the concentrations of these substances are found to be similar in both groups. It is obvious, however that the concentrations in children with Alport-syndrome lie mainly in the upper range, while these with Pendred-syndrome have values in the lower range of the total distribution curve.