OBJECTIVETo investigate the molecular mechanism of a Chinese patient with 46, XY sex reversal.

METHODSDNA fragments of the SRY gene from the typical XY female sex reversal patient and her father were amplified by polymerase chain reaction (PCR). The amplified PCR fragments were cloned into the pUCm-T vector, and direct sequencing was carried out on an ABI 377-3 automated DNA sequencer to detect the mutation. PCR-restriction enzyme digestion was applied to detect the results of DNA sequencing.

RESULTSA novel mutation of the SRY gene was identified in the XY sex reversal patient of this study. A T is replaced by an A in codon 129 at position +387, resulting in the replacement of the polar amino acid tyrosine (TAT) by the stop code (TAA) in the HMG-box, whereas her father was proved to have the wild-type sequence. Because the mutation introduced an enzyme site of MaeIII, the PCR-restrict enzyme digestion showed that there were three bands (131 bp,231 bp and 247 bp) in the patient, whereas two bands (131 bp and 478 bp) in normal man. It verified the results of sequencing analysis. The results after searching the Human Gene Mutation Database showed that this mutation was not described before and should be a new mutation.

CONCLUSIONThe novel mutation in SRY gene has provided valuable information for the understanding of molecular mechanism of the patient with 46,XY female sex reversal.