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The aim of this study was to investigate the genetic polymorphism of 20 short tandem repeat (STR) loci including D1S1656, D2S1338, D3S1358, D5S818, D6S1043, D7S820, D8S1179, D12S391, D13S317, D16S539, D18S51, D19S433, D21S11, CSF1PO, FGA, Penta D, Penta E, TH01, TPOX, and vWA in Han population of Henan, China and to assess its value in forensic science. Genomic DNA was extracted from 274 blood samples of unrelated healthy individuals in the Henan Han population. Alleles were amplified with PowerPlex® 21 system kit and PCR products were detected with ABI3130 genetic analyzer (Applied Biosystems) and the data were analyzed with modified PowerStats v1.2. A total of 229 alleles were observed in this Han population and the allelic frequencies ranged from 0.0020 to 0.5090 in the present study. Observed genotype distributions for each locus do not show deviations from Hardy–Weinberg equilibrium expectations (p < 0.05). The combined power of discrimination, combined power of exclusion, and combined matching probability of this 20 STR loci were 0.999999999, 0.999999994603, and 4.0433 × 10−24, respectively. The 20 STR loci are highly polymorphic in the Han population of Henan, China and they may be of great value in forensic science and human population genetics.

Background Desbuquois dysplasia (DBQD) was a rare autosomal recessive skeletal dysplasia. Calcium activated nucleotidase 1 (CANT1) mutation was identified as a common pathogenic change for DBQD type 1 and Kim variant but not for DBQD type 2. To our knowledge, all patients with DBQD type 1 currently found could be explained by mutations in the CANT1 gene, but mutations in the CANT1 gene might not be directly diagnosed as DBQD type 1. Results We have identified two novel CANT1 mutations (mut1: c.594G > A [p.Trp198*], mut2: c.734C > T [p.Pro245Leu]) in three children from a family of Chinese origin for the first time. Two of the three children could be diagnosed as typical DBQD type 1 and one child could not be diagnosed as DBQD type 1 based on the clinical data we had. To further clarify the effect of the two mutations of the CANT1 gene, we studied the CANT1 gene expression and detected the protein secretion and nucleotide enzyme activity through cDNA cloning and expression vectors construction for wild and mutant types. The mut1 was a nonsense mutation which could lead to premature termination and produced the truncated bodies; The CANT1 dimer of mut2 was significantly reduced and even undetectable. The extracellular secretion of mut1 was extremely high while mut2 was significantly reduced compared with the wild type. And mut1 and mut2 also could result in a significant reduction in the activity of CANT1 nucleotidease. From the results we could deduce that the two mutations of the CANT1 gene were the causes of the two cases in this study. Conclusions Regarding the particularity of the cases reported in this study, the pathogenesis of CANT1 might be more complicated. The genetic and phenotype of three children with the same genetic background need to be further studied. Larger cohort of patients was needed to establish genotype–phenotype correlations in DBQD.

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