Effect of uniparental disomy in parentage testing.

Uniparental disomy (UPD) is a rare type of chromosomal aberration that may hinder the analysis of kinship during forensic identification. Here, we investigated these genetic findings to avoid false exclusions during parentage testing. Thirty-nine fluorescently labeled, autosomal short tandem repeats (STR) were amplified in three cases, to detect parent-child relationships. Twenty-three fluorescently labeled Y-chromosome STRs were also employed. These were subjected to capillary electrophoresis. The parentage index was calculated by the bipartite or tripartite model. Single nucleotide polymorphism (SNP) microarrays were performed to further investigate the genetic mechanisms. The conclusions supported the biological mother-child relationship in three cases. However, in all cases, the alleged father and child had three autosomal STR markers, constrained to a single chromosome, which did not conform to Mendelian inheritance rules. The genotyping of 23 Y-chromosome STRs did not reveal any violations of Mendelian law. The combination of STR profiling and SNP microarrays suggested that two children had maternal UPD of chromosome 7, whilst one had UPD of chromosome 2. After excluding the three incompatible loci, the conclusions supported the biological father-child relationship in all cases. The same results were obtained when parentage testing of trios was used. Uniparental disomy may complicate the judgment of kinship in parentage testing. The possibility of UPD should be considered when incompatible STR loci are found on the same chromosome. Genetic evidence obtained through additional molecular techniques can provide better interpretation of kinship in the presence of UPD and avoid false exclusions of biological relationships.

[Analysis of copy number variation in AZF region of Y chromosome in patients with spermatogenic failure].

OBJECTIVE: To explore the characteristics of copy number variation (CNV) within the Y chromosome azoospermia factor (AZF) region in patients with spermatogenesis disorders in the Shenzhen area. METHODS: A total of 123 patients with spermatogenesis disorders who had visited Shenzhen People's Hospital from January 2016 to October 2022 (including 73 patients with azoospermia and 50 patients with oligozoospermia) and 100 normal semen males were selected as the study subjects. The AZF region was detected with multiplex ligation-dependent probe amplification (MLPA), and the correlation between the CNV in the AZF region and spermatogenesis disorders was analyzed using the chi-square test or Fisher's exact test. RESULTS: 19 CNV were detected among 53 patients from the 223 samples, including 20 cases (27.40%, 20/73) from the azoospermia group, 19 cases (38%, 19/50) from the oligozoospermia group, and 14 cases (14%, 14/100) from the normal control group. In the azoospermia, oligozoospermia, and normal control groups, the detection rates for CNV related to the AZFa region (including AZFab and AZFabc) were 5.48% (4/73), 2.00% (1/50), and 0 (0/100), respectively. The detection rates for the AZFb region (including the AZFbc region) were 6.85% (5/73), 0 (0/50), and 0 (0/100), respectively. The detection rates for gr/gr deletions in the AZFc region were 2.74% (2/73), 6.00% (3/50), and 9.00% (9/100), respectively, and those for b2/b4 deletions in the AZFc region were 2.74% (2/73), 10.00% (5/50), and 0 (0/100), respectively. The detection rates for complex rearrangements in the AZFc region were 6.85% (5/73), 18.00% (9/50), and 3.00% (3/100), respectively. Statistical analysis showed no significant difference in the detection rate of gr/gr deletions between the three groups (Fisher's Exact Test value = 2.712, P = 0.249); the differences in the detection rate of b2/b4 deletions between the three groups were statistically significant (Fisher's Exact Test value = 9.489, P = 0.002); the differences in the detection rate of complex rearrangements in the AZFc region between the three groups were statistically significant (Fisher's Exact Test value = 9.493, P = 0.006). In this study, a rare AZFa region ARSLP1 gene deletion (involving SY86 deletion) was detected in a patient with oligozoospermia. CONCLUSION: CNV in the AZFa and AZFb regions have a severe impact on spermatogenesis, but partial deletion in the AZFa region (ARSLP1 gene deletion) has a minor impact on spermatogenesis. The b2/b4 deletion and complex rearrangement in the AZFc region may be risk factors for male infertility. The gr/gr deletion may not serve as a risk factor for male infertility in the Shenzhen area.

A novel nonsense mutation in MYO15A is associated with non-syndromic hearing loss: a case report.

BACKGROUND: Hearing loss is genetically heterogeneous and is one of the most common human defects. Here we screened the underlying mutations that caused autosomal recessive non-syndromic hearing loss in a Chinese family. CASE PRESENTATION: The proband with profound hearing loss had received audiometric assessments. We performed target region capture and next generation sequencing of 127 known deafness-related genes because the individual tested negative for hotspot variants in the GJB2, GJB3, SLC26A4, and MTRNR1 genes. We identified a novel c.6892C > T (p.R2298*) nonsense mutation and a c.10251_10253delCTT (p.F3420del) deletion in MYO15A. Sanger sequencing confirmed that both mutations were co-segregated with hearing loss in this family and were absent in 200 ethnically matched controls. Bioinformatics analysis and protein modeling indicated the deleterious effects of both mutations. The p.R2298* mutation leads to a truncated protein and a loss of the functional domains. CONCLUSIONS: Our results demonstrated that the hearing loss in this case was caused by novel, compound heterozygous mutations in MYO15A. The p.R2298* mutation in MYO15A was reported for the first time, which has implications for genetic counseling and provides insight into the functional roles of MYO15A mutations.

Mitochondrial DNA polymorphisms in Gelao ethnic group residing in Southwest China.

Gelao ethnic group, an aboriginal population residing in southwest China, has undergone a long and complex evolutionary process. To investigate the genetic structure of this ancient ethnic group, mitochondrial DNA (mtDNA) polymorphisms of 102 Gelao individuals were collected and analyzed in this study. With the aid of the information extracted from control-region hypervariable segments (HVSs) I and II as well as some necessary coding-region segments, phylogenetic status of all mtDNAs under study were determined by means of classifying into various defined haplogroups. The southern-prevalent haplogroups B, R9, and M7 account for 45.1% of the gene pool, whereas northern-prevalent haplogroups A, D, G, N9, and M8 consist of 39.2%. Haplogroup distribution indicates that the Gelao bears signatures of southern populations and possesses some regional characters. In the PC map, Gelao clusters together with populations with Bai-Yue tribe origin as well as the local Han and the Miao. The results demonstrate the complexity of Gelao population and the data can well supplement the China mtDNA database.

[GJB2 gene mutation in deaf patients].

OBJECTIVE: To detect the GJB2 gene mutation in patients with autosomal-recessive deafness, and analyze the relationship between clinical phenotype and gene mutation. METHODS: Forty-two patients were examined clinically by pure tone audiometry, acoustic impedance and auditory brainstem response. The complete coding region of the GJB2 gene was amplified by polymerase chain reaction (PCR) and the PCR products were subjected to automatic DNA sequencing. RESULTS: Two cases had homozygous mutation of 235delC. One of them had sensorineural hearing loss while the other had mixed hearing loss. Heterozygous mutation of 176del16bp was detected in a pair of twins who had mixed hearing loss. The 109G to A, 79G to A and 341A to G mutations were observed in both the patients and the controls. CONCLUSION: Homozygous 235delC mutation is one of the pathogeni c mutations which could occur in patients with mixed hearing loss. The heterozygous 176del16bp mutation combined with environmental factor may cause hearing loss. The 109G to A, 79G to A and 341A to G variants were considered to be polymorphisms of the GJB2 gene.

[The relationship between the effect of amlodipine on carotid intimal-medial thickness and angiotensin converting enzyme genotypes in elderly hypertensive patients].

OBJECTIVE: To investigate the association between the anti-atherosclerotic effects of amlodipine and angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in elderly essential hypertensive (EH) patients. METHODS: A total of 220 EH patients were treated with amlodipine (2.5 - 10 mg, once daily) for twelve months and complete data were obtained from 208 patients with genotypes of II (n = 90), ID (n = 91) and DD (n = 27). The indices of carotid arterial were compared before and post amlodipine treatment in patients with identical genotype and among different ACE genotypes and each genotype post therapy. RESULTS: The carotid mean intimal-medial thickness (MIMT) was slightly decreased in EH patients with ID and DD genotypes and significantly decreased in EH patients with II genotype (0.96 +/- 0.12 vs. 0.92 +/- 0.13, P < 0.01) compared to pre-treatment values. The decreased degree of MIMT (DeltaMIMT) in II genotype was significantly higher in II genotype than those in ID or DD genotype (0.05 +/- 0.03 vs. 0.01 +/- 0.02, 0.01 +/- 0.03 respectively, P < 0.01). The post treatment plaque score (PS) in patients with II genotype was significantly reduced (4.85 +/- 2.51 vs. 3.90 +/- 2.36, P < 0.05). Multivariate linear regression analysis showed the baseline SBP, the decreased degree of SBP (DeltaSBP) and the II genotype were the major factors affecting the DeltaMIMT. CONCLUSION: Hypertensive patients carrying II genotype ACE genotype are the best responders for the anti-atherosclerotic effects of amlodipine.

Analysis of mitochondrial DNA polymorphisms in Guangdong Han Chinese.

Previous investigations on Chinese mitochondrial DNA (mtDNA) variation revealed that the matrilineal gene pool of southern Han Chinese is rather complex, with much higher genetic diversity and more basal/ancient lineages than the northern Hans. The extreme case is Guangdong Han populations, among which pronounced (matrilineal) differentiation has been observed, indicative of complex demography of the region. To get more insights into the maternal makeup of southern Han Chinese, mtDNA variation of a total of 106 individuals sampled from Dongguan, Guangdong Province, China, was analyzed in this study. With the aid of the information from control-region hypervariable segments I and II (HVS-I and -II) as well as some necessary coding-region segments, the phylogenetic status of all mtDNAs under examination were determined according to the reconstructed East Asian mtDNA tree. In this way, the mtDNAs have been classified into various haplogroups or sub-haplogroups. The southern-prevalent haplogroups, such as R9 (20.8%), B (17.9%), M7b (14.2%), show relatively high distribution frequencies in Dongguan Hans; whereas the frequencies of Northern-prevalent haplogroups (with the exception of D) are quite low: C (1.9%), G2 (1.9%) and Z (1.9%), indicating the southern-origin of Dongguan Hans.

[A recurrent rhodopsin gene missense mutation in a Chinese family with autosomal dominant retinitis pigmentosa].

OBJECTIVE: To detect mutation in the rhodopsin gene (RHO) in a Chinese family with autosomal dominant retinitis pigmentosa (ADRP). METHODS: A total of 25 family members from a Chinese family were investigated. All the subjects were examined clinically by direct funduscopy, perimetry and vision test. Evaluation of the proband included electroretinography (ERG). Genomic DNA was extracted using standard method. The complete coding regions of RHO were amplified by polymerase chain reaction (PCR) and the PCR products were subjected to automatic DNA sequencing. RESULTS: 512 C>T (P171L), a recurrent missense mutation was detected in the proband. All 12 affected subjects in the family were heterozygous for the mutation. The affected individuals had night blindness at the age of 5-6 years. They had relatively severe impairment of visual acuity and suffered a gradual loss of peripheral visual field at the age of 20-30 years. And they went blind at the age of 40-50 years. Rod and cone ERG were not detectable in the proband. CONCLUSION: A recurrent missense mutation, 512C>T (P171L), was detected in a Chinese family with ADRP.

[Effects of bu yang huan wu decoction on astrocytes after cerebral ischemia and reperfusion].

OBJECTIVE: To study the effects of Bu Yang Huan Wu Decoction on astrocytes after cerebral ischemia and reperfusion. METHOD: Cerebral ischemia model in gerbils was produced by ligating bilateral common carotid artery. The dynamic expressin of GFAP were determined by immunochemistry after cerebyal ischemia for 15 min followed by reperfusion for 24 hours and 48 hours. RESULT: GFAP positive reactions reached a peak after cerebral ischemia for 15 min followed by reperfusion for 24 hours. Bu Yang Huan Wu Decoction decreased the expression. GFAP positive reactions decreased after cerebral ischemia for 15 min followed by reperfusion for 48 hours, Bu Yang Huan Wu Decoction increased the expression. CONCLUSION: The regulation of Bu Yang Huan Wu Decoction on astrocytes after cerebral ischemia and reperfusion may be related to repairing process after cerebral ischemia.