Application of Multiple Kits in Special Parentage Testing Cases / 法医学杂志

OBJECTIVES@#To analyse the genetic polymorphism of 21 autosome STR loci in Han population of Shandong Province and the cases with loci mutation or allelic loss typed by Goldeneye® DNA identification system 25A.@*METHODS@#Totally 40 autosome STR loci types of 273 unrelated individuals in Han population of Shandong Province were typed by Goldeneye® DNA identification system 25A and 22NC, and the genetic polymorphism of 21 STR loci in those was analysed. Meanwhile, six cases with loci mutation were analysed by adding the tests with Goldeneye® DNA identification system 22NC, 20Y and 17X. Another three cases with allelic loss were tested by AmpFℓSTR® Identifiler® Plus PCR and analysed by gene sequencing.@*RESULTS@#The genetic parameters of 21 autosome STR loci in Han population of Shandong Province were obtained. When STR loci were added up to 40, five of those with loci mutation met the identification requirements, and the results of X-STR or Y-STR types were consistent with that of STR loci. There was another duo case with one suspected loci mutation, biological source of six STR loci genotypes could not be found in the genotypes of supposed father. The Y-STR genotype of two individuals was identical that indicated both of them came from same paternal line. However, the fatherhood was excluded according to the autosome STR loci system. For two cases with allelic loss on D18S51, base mutation or loss were found in the primer binding domain of mother and child by gene sequencing. Another mother-child case with allelic loss on D13S317 was certified by AmpFℓSTR® Identifiler® Plus PCR kit.@*CONCLUSIONS@#The 21 autosome STR loci in Han population of Shandong Province have high polymorphism, which can be used in routine cases of paternity identification. For some duo cases with loci mutation, Goldeneye® DNA identification system 25A cannot satisfy the identification requirements, thus more autosome STR loci should be added properly. For the cases with allelic loss, the problem can be resolved by gene sequencing or using different merchant kits.

Detection and Analysis of 12 Suspected Amelogenin Allelic Loss Cases / 法医学杂志

OBJECTIVES@#To observe and analyse the Amelogenin allelic loss in parent-child identification cases, and to explore the type and mechanism of Amelogenin allelic loss as well as its influence on gender identification and solutions.@*METHODS@#After the detection by SiFaSTR™ 23plex DNA identification system, samples had the characteristics of the peak area of Amelogenin X was the same as the one of adjacent heterozygote or lower than one half of adjacent homozygote in females while Amelogenin X loss was observed in males were selected. X chromosome STR （X-STR） typing and Amelogenin X sequencing were performed. The samples with Amelogenin Y loss in males were confirmed by the detection of Y chromosome STR typing and sex-determining region of Y （SRY）. The type and rate of Amelogenin allelic loss were confirmed and calculated, and the mechanism and influence of this variation were also analysed.@*RESULTS@#Amelogenin X allelic loss was observed in one male sample, the mutation in primer-binding region was confirmed by sequencing. The suspected Amelogenin X allelic loss was observed in four female samples, but the mutation in primer-binding region was confirmed by sequencing in only one sample. Amelogenin Y allelic loss was observed in seven male samples, SRY positive cases was detected in five of them, and two were SRY negative. Y-STR type was detected in four cases of the five SRY positive cases, which was not detected in the two SRY negative cases. The rate of Amelogenin allelic loss was about 0.029%.@*CONCLUSIONS@#Amelogenin X allelic loss does not affect the gender identification, but Amelogenin Y allelic loss may cause wrong gender identification. Thus, Y-STR or SRY should be detected for gender confirmation. When Y-STR genotypes are not detected in a "male" whose SRY detection is also negative, then the chromosome karyotype analysis and sex differentiation related genes test should be taken to further confirm the gender.