BACKGROUND: 5α steroid reductase deficiency (5αSRD) is an autosomal recessive 
enzymatic deficiency and mutations in the 5α steroid reductase type 2 gene 
(SRD5A2) result in male pseudohermaphrodism caused by decreased 
dihydrotestosterone (DHT) synthesis.
AIM: To identify the specific mutations of the SRD5A2 gene in Cypriot patients 
with 5αSRD.
SUBJECTS AND METHODS: Five unrelated patients with 46,XY karyotype were 
examined. Four of them were born with ambiguous genitalia and 1 patient, who was 
raised as girl, presented with primary amenorrhea. The hCG test was informative 
(elevated testosterone/DHT) of 5αSRD in 3 out of 4 subjects. Sequencing of the 
SRD5A2 gene was completed for all patients. Genomic DNA was also isolated from a 
total of 204 healthy unrelated Cypriot subjects. Screening for the IVS1-2A>G 
mutation was performed by using direct sequencing and restriction enzyme 
analysis.
RESULTS: The IVS1-2A>G was identified in homozygosity in 3 patients and in a 
compound heterozygote state in the other 2 patients, in combination with p.P181L 
and p.R171S in exon 3, respectively. The carrier frequency in the Cypriot 
population for the IVS1-2A>G mutation was estimated to be 0.98% or 2 in 204.
CONCLUSIONS: The same IVS1-2A>G mutation in the SRD5A2 gene seems to 
characterize all Cypriot patients with 5αSRD diagnosed so far. Furthermore this 
relatively rare genetic defect, which has only been reported previously in a 
single case in the Eastern Mediterranean region, is very likely to be the result 
of a founder effect.