An improved procedure for detection of hypoxanthine--guanine phosphoribosyl transferase heterozygotes.

The absence of activity of the enzyme hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) is known to be the cause of the Lesch-Nyhan syndrome. Previous methods for detection of heterozygous carriers of this genetic defect either are quite time consuming, require specialized equipment, or lack the necessary sensitivity. We present here a method in which thin-layer chromatography and autoradiography are used to assay the activity of this enzyme in individual hair roots collected from the scalp of the possible carrier. This method is fast and sensitive, and requires no specialized equipment.