Classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency in Croatia between 1995 and 2006

To evaluate the incidence, gender, symptoms and age at diagnosis of patients with classical congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency in Croatia.

Data were collected retrospectively for all classical CAH patients born or electively aborted following prenatal diagnosis between January 1, 1995 and December 31, 2006 and were compared with the data of a previously conducted study evaluating CAH patients discovered between 1964 and 1984.

During a 12-year period 34 classical CAH patients were born. There were 20 salt-wasting (SW; 12 female/8 male) and 14 simple-virilizing (SV; 7 female/7 male) patients. If 3 female, electively aborted fetuses were added, there would be a total of 37 CAH patients. With 532,942 live births and 34 CAH patients born over this period, the incidence of classical CAH was estimated at 1:15,574 or 1:14,403 if the 3 electively aborted fetuses were included. The lower incidence of SW boys compared to SW girls (8:12) and similar number of SW and SV boys (8:7) indicate that a substantial proportion of SW boys die unrecognized. Owing to better healthcare, the diagnosis was established significantly earlier in SW and SV girls compared to the period of 1964-1984 (p < 0.003). During 1995-2006, none of the patients died following the diagnosis of CAH and there was no erroneous sex assignment.

Despite improvements in healthcare, the diagnosis of CAH in Croatia is still delayed and some of the patients go unrecognized or die. Therefore, the results of our study support the need to introduce newborn screening.