The Application of X-STR: Two Case Reports

The usefulness of the X-chromosomal STRs (short tandem repeats) for forensic purposes seems to be restricted, but may be valuable in some paternity cases. Due to the particular mode of inheritance, X-chromosomal X-STR has the advantage in female traces identification against male contamination and in complex kinship cases, such as deficiency cases (mother-son or father-daughter), grandparent-grandchild comparisons, half-sisters testing, etc. In this study, 4 blood samples from two paternity cases without father were examined with TYPER19 Amplification kit first, from the result, it is hard to judge the relationship between the mother-sons, then TYPERX19 kit was conducted to obtain the full profiles of the two pairs of the mother-son, from the genetypes of the samples, it can be inferred that neither of the two pairs of mother-son were in line with the kinship, which provides important evidence for the two paternity cases. All together, the X-chromosome marks included in the TYPERX19 kit can offer the possibility to solve complex kinship cases where autosomal STR markers cannot provide the information needed.