Cystic fibrosis and deafness.

Abstract

During our preliminary molecular survey of the cystic fibrosis (CF) AF508 mutation in 18 patients selected by positive sweat tests, we found one patient with agenesis of the cochlea (Mondini's syndrome), several bouts of dehydration, and absence of pulmonary digestive complications. This 12 year old girl was born to unrelated, non-Caucasian parents and a heterozygous AF508/ non-AF508 genotype was found in her lymphocytes. In our study only 33.5% of patients were found to be homozygous for the classical CF mutation, 11.8% were heterozygous, and the remaining majority of patients were not carriers of the AF508 mutation. As expected in our mixed non-Caucasian population, several other combinations of CF mutations may be found in a rather different distribution compared to European countries. Recently, Raskin et all showed that 46% of their patients in a more homogeneous racial region of Brazil were homozygous for the AF508 mutation. As a consequence, minor and uncommon clinical presentations of CF would be expected to occur in our population. Our patient with sensorineural deafness as a result of agenesis of the cochlea could have resulted from a similar mechanism to, for example, congenital agenesis of the vas deferens in infertile males, in whom CF mutations have recently been reported.2 It is possible in our population that CF patients may be found more frequently in different clinics seeking medical attention for other reasons than those expected in classical CF patients.