Deletion mapping and paternal origin of a Mexican AMELY negative male

[Molecular-genetic analysis of a rare forensic case of partial deletion of the Y-chromosome]

The amelogenin gene encodes dental enamel protein and is present in humans in two forms - AMELX and AMELY, located on the X- and Y-chromosomes, respectively. This rare case depicts a partial deletion of the AMELY gene. In the Into-Stil LLC laboratory, we performed the genetic testing of the DNA samples extracted from buccal epithelial cells of the alleged father and the disputed child (a boy). Genotyping was carried out using COrDIS Plus ('Gordis', Russian Federation) and AmpFLSTR Identifiler Direct PCR Amplification ('Applied Biosystems', USA) Kits. Our findings have demonstrated that both the alleged father and the disputed child lacked the fragments corresponding with the AMELY gene. Using both STR-systems, we detected, in the disputed child's genome, the allele formally identical to the allele in the genome of the alleged father. Further analysis using the COrDYS ('Gordis', Russian Federation) kit allowed us to detect the amplified fragments corresponding with all the STR loci of Y chromosome, except DYS576 and DYS449, which confirmed that both studied individuals belonged to male biological sex.

Whole Genome Amplification of Day 3 or Day 5 Human Embryos Biopsies Provides a Suitable DNA Template for PCR-Based Techniques for Genotyping, a Complement of Preimplantation Genetic Testing

Our objective was to determine if whole genome amplification (WGA) provides suitable DNA for qPCR-based genotyping for human embryos. Single blastomeres (Day 3) or trophoblastic cells (Day 5) were isolated from 342 embryos for WGA. Comparative Genomic Hybridization determined embryo sex as well as Trisomy 18 or Trisomy 21. To determine the embryo's sex, qPCR melting curve analysis for SRY and DYS14 was used. Logistic regression indicated a 4.4%, 57.1%, or 98.8% probability of a male embryo when neither gene, SRY only, or both genes were detected, respectively (accuracy = 94.1%, kappa = 0.882, and p < 0.001). Fluorescent Capillary Electrophoresis for the amelogenin genes (AMEL) was also used to determine sex. AMELY peak's height was higher and this peak's presence was highly predictive of male embryos (AUC = 0.93, accuracy = 81.7%, kappa = 0.974, and p < 0.001). Trisomy 18 and Trisomy 21 were determined using the threshold cycle difference for RPL17 and TTC3, respectively, which were significantly lower in the corresponding embryos. The Ct difference for TTC3 specifically determined Trisomy 21 (AUC = 0.89) and RPL17 for Trisomy 18 (AUC = 0.94). Here, WGA provides adequate DNA for PCR-based techniques for preimplantation genotyping.

Deletion mapping of the regions with AMELY from two Chinese males

The amelogenin (AMEL) is widely used in many multiplex PCR kits for gender determination. However, the null of amelogenin Y (AMELY) can result in the incorrect genotyping of male samples as females. In this study, we report the deletion of AMELY in two cases with a deletion frequency of 0.019% (2/10526) in our laboratory. The deletion region with AMELY was mapped by using other twelve loci, which shows the class I deletion pattern. Further, the Y chromosome short tandem repeat (Y-STR) typing shows that these two cases share the same haplotype with other two cases from previous reports. The haplogroup of the two cases was predicted as O3 haplogroup with a 100% probability. Altogether, this study will provide evidence to further demonstrate the deletion of AMELY in Chinese population.