Objective: To investigate the types and frequencies of variants in Amelogenin gene in Chinese population and to explore the mutations' influence to the sex test.

Methods: The Amelogenin gene of 8850 unrelated Chinese individuals was typed with PowerPlex 16 system. The samples with abnormal typing results were calculated directly, validated with different primer sets, Y-STR typing and sequencing.

Results: Two samples with X chromosomal Amelogenin (AMELX) allelic dropout and 2 samples with Y chromosomal Amelogenin (AMELY) allelic dropout were observed in male individuals, the total rate of mutation was 0.045% and the rate in the male was 0.085%. Two types of point mutation which may result in null allele were observed in the primer binding region of the plostq AMELX alleles, and the mutation rate in the male was 0.042%. The mutation rate of AMELY allele was also 0.042%. One sample failed to amplify 10 Y-STR loci out of 12 loci, which could be speculated that large interstitial deletion of the Y chromosome encompassing the AMELY and other Y-STR loci occurred.

Conclusion: AMELX or AMELY allelic dropout may occur due to the mutation of Amelogenin gene, which may interfere with the sex test and induce wrong gender identification.