Preliminary Reference Interval for 5-Alpha Reductase in Normal Male Children and Its Association with Hypospadias

5-alpha reductase (5-AR) enzyme is responsible for conversion of testosterone to dihydrotestosterone (DHT) in humans, which subserves various functions. The aim of the study was to establish a normal reference interval (RI) for blood levels of the enzyme 5-AR.

We conducted a prospective study on 150 boys, 75 of whom underwent circumcision for various benign conditions or for religious reasons (Group A/controls) and 75 suffering from hypospadias of variable severity (Group B/cases). The plasma levels of 5-AR were measured by enzyme-linked immunosorbent assay (ELISA) in all 150 boys and correlated with the severity of hypospadias.

The 5-AR levels in Group A ranged from 14.6 to 17.3 ng/mL. The enzyme levels decreased in value with increasing severity of hypospadias in Group B (P-value <0.01 - statistically significant). The levels of the enzyme in this group ranged from 0.6 ng/mL (in the most severe variety of hypospadias) to 11.5 ng/mL (mild variety of hypospadias).

There is no record of RI values of 5-AR in the literature. The RI of 5-AR needs to be determined by conducting more studies globally. Its levels falls considerably with clinical severity of hypospadias, reinforcing the importance of the enzyme in the development of male external genitalia.