Salt-wasting congenital adrenal hyperplasia: genotypical peculiarities in a Sicilian ethnic group.

Here we report for the first time the results of the molecular study of 17 unrelated patients with salt-wasting (SW) congenital adrenal hyperplasia (CAH) belonging to a Sicilian ethnic group, as corroborated by patients' pedigree taken to include 2 generations in the paternal and maternal lineage. The aim of this report was to confirm that genetic basis of CAH may be characterized by population differences. In our series, the overall predominant mutation was IVS2A/C>G, that was detected in 50% of alleles and in 58.8% of patients. The allelic and homozygous frequencies of IVS2A/C>G, Del8bpE3, and R356W mutations were significantly higher in our series than in other populations. Our study population included 2 cases with 2 different mutations that have been recently reported for the first time, 3 cases with a double mutation on the same allele, and 1 case with homozygous de novo mutation. We concluded that: a) in a Sicilian ethnic group the most frequent genotype in SW CAH is IVS2A/C>G homozygocity; b) surprisingly Del8bpE3 and R256W homozygocity are also well represented.

In Sicilian ethnic group non-classical congenital adrenal hyperplasia is frequently associated with a very mild genotype.

The spectrum of mutated alleles in non-classical congenital adrenal hyperplasia (NC-CAH) has been recently reported to be very large and haplotypes may significantly differ in the different ethnic groups. In order to confirm that population differences may exist in the genetic basis of this disease, we have analyzed the genetic presentation of NC-CAH in a Sicilian cohort of symptomatic patients and compared our findings with the ones reported in other studies of different ethnic groups. In 38 NC-CAH patients coming from two regions of Sicily and born of Sicilian parents, we found that 84.2% of the chromosomes examined bore only mild mutations and only the remaining 15.8% of the chromosomes bore at least 1 severe mutation. The overall predominant mutation was V281L, which was detected in 73.7% of alleles and in 89.5% of patients. About 58% of the patients were homozygotes for this mutation. V281L allele and homozygote frequencies were higher in the present series than in other European and Italian reports. In our NC-CAH population, which is one of the largest ever reported, the patients with two mild mutations exhibited a less severe impairment of both clinical and endocrine phenotype. On the basis of these results we can conclude that: a) in Sicilian ethnic groups NC-CAH is frequently associated with a very mild genotype; b) the most frequent genotype in our series is V281L homozygosis; c) clinical and biochemical expression of NC-CAH is more marked in the patients bearing a severe mutation; d) no correlations between genotype and phenotype were found in our patients affected by NC-CAH.