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.
Amelogenin/genetics* ; DNA/genetics* ; Female ; Humans ; Loss of Heterozygosity/genetics* ; Male ; Sex Determination Analysis

OBJECTIVES: To observe and analyze the confirmed cases of paternity testing, and to explore the mutation rules of STR loci. METHODS: The mutant STR loci were screened from 20 723 confirmed cases of paternity testing by Goldeneye 20A system．The mutation rates, and the sources, fragment length, steps and increased or decreased repeat sequences of mutant alleles were counted for the analysis of the characteristics of mutation-related factors. RESULTS: A total of 548 mutations were found on 19 STR loci, and 557 mutation events were observed. The loci mutation rate was 0.07‰-2.23‰. The ratio of paternal to maternal mutant events was 3.06:1. One step mutation was the main mutation, and the number of the increased repeat sequences was almost the same as the decreased repeat sequences. The repeat sequences were more likely to decrease in two steps mutation and above. Mutation mainly occurred in the medium allele, and the number of the increased repeat sequences was almost the same as the decreased repeat sequences. In long allele mutations, the decreased repeat sequences were significantly more than the increased repeat sequences. The number of the increased repeat sequences was almost the same as the decreased repeat sequences in paternal mutation, while the decreased repeat sequences were more than the increased in maternal mutation. CONCLUSIONS There are significant differences in the mutation rate of each locus. When one or two loci do not conform to the genetic law, other detection system should be added, and PI value should be calculated combined with the information of the mutate STR loci in order to further clarify the identification opinions.
Alleles ; DNA Mutational Analysis/methods* ; Family ; Genetic Loci ; Humans ; Male ; Microsatellite Repeats ; Mutation ; Mutation Rate ; Paternity

Objective:To simulate the placement of percutaneous cortical bone trajectory (CBT) screws on reconstructed CT images and three-dimensional lumbar model and to measure the morphometric parameters for guiding the placement of percutaneous CBT screws.Methods:The CT images of 100 adult patients with lumbar spine diseases were studied. The CT images were reconstructed using Mimics software. Taking the projection point on the lamina at the junction of the inner and lower edge of the smallest coronal section of lumbar pedicle as the entry point, the cephalad angle, lateral angle, maximum screw length, maximum screw diameter, distance between trajectory and spinous process were measured. At the same time, the relationship between the trajectory and spinous process was observed by using the reconstructed three-dimensional image.Results:The lateral angle of the trajectory from L 1 to L 5 were 9.3° (8.9°, 9.8°), 9.6° (8.9°, 9.8°), 10.4° (9.5°, 11.3°), 11.81°±1.24° and 13.6° (12.5°, 14.5°), respectively. The cephalad angle from L 1 to L 5 were 26.6° (26.0°, 27.0°), 26.2° (25.7°, 26.5°), 26.9° (26.5°, 27.4°), 25.94°±0.92° and 24.3° (22.7°, 25.4°), respectively. Significant statistic differences were found among all levels in the cephalad angles and lateral angles. The mean diameters of the trajectory from L 1 to L 5 were 5.65±0.49 mm, 6.38±0.60 mm, 6.91±0.67 mm, 7.42±0.76 mm and 8.33 (7.59, 9.01) mm, respectively. Except L 1 and L 5, there were significant differences among all levels in the maximum screw diameters. The mean length of the trajectory from L 1 to L 5 were 36.4 (35.4, 37.0) mm, 36.7 (35.8, 37.3) mm, 37.6 (37.1, 38.1) mm, 37.8 (37.3, 38.1) mm and 36.2 (35.2, 36.9) mm, respectively, and there were also significant differences among all levels. The ration in superior endplate for each segment were 41.08% (34.36%, 45.60%), 37.94% (32.97%, 43.63%), 40.18% (34.56%, 44.49%), 38.61% (34.80%, 46.24%) and 40.9% (35.32%, 46.02%), respectively and statistical differences were significant between L 1 and L 2 and L 2 and L 5. The mean distance between the trajectory and the spinous process from L 1 to L 5 were 7.27±1.23 mm, 7.19 (5.97, 8.28) mm, 7.32 (6.01, 8.28) mm, 7.31±1.36 mm and 7.45 (6.32, 8.23) mm, respectively. In the sagittal CT image, the tip of the trajectory located near the posterior two-fifths of the superior end plate, and the extended line of the trajectory located at the inferior edge of spinous process. In the three-dimensional reconstruction model, no obstruction was found between the simulated screws and the spinous process. Conclusion:Lumbar CBT screw can be implanted percutaneously, and spinous process will not hinder the implantation process. Spinous process and upper endplate can be used as a sign to guide the percutaneous CBT screw implantation. Digital analog screw placement can offer a useful reference for the clinical application of percutaneous cortical bone trajectory screw.