Molecular genetics study of ED1 gene for two X-linked hypohidrotic ectodermal dysplasia families / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide genetic diagnosis and counseling for patients from two families affected with X-linked hypohidrotic ectodermal dysplasia.</p><p><b>METHODS</b>Potential mutation of the ED1 gene was screened by DNA sequencing. For family 1, multiplex ligation-dependent probe amplification (MLPA) analysis and haplotyping of ED1 gene were also carried out for prenatal diagnosis.</p><p><b>RESULTS</b>For the patient from family 1, deletion of the exon 1 of the ED1 gene and 2 short tandem repeat(STR) sites (DXS8269 and DXS1422) were detected. His daughter was carrier of the deletion. Upon prenatal diagnosis, the fetus was confirmed to be a normal male, for whom the haplotype of ED1 gene has differed from that of the proband. In family 2, a c.463C>T mutation in exon 3 of the ED1 gene was detected in the proband, whose mother was heterozygous for the same mutation.</p><p><b>CONCLUSION</b>The deletion (exon 1) and missense (R155C) mutation in ED1 gene have probably underlied the disease in the two families. During prenatal diagnosis, it may be necessary to obtain precise results through combining mutation detection and haplotype analysis of the ED1 gene.</p>

Mutation analysis and prenatal diagnosis of families affected with Duchenne and Becker muscular dystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To detect potential mutations for probands from families affected with Duchenne/Becker muscular dystrophy (DMD/BMD), and to carry out prenatal diagnosis through identification of female carriers.</p><p><b>METHODS</b>A total of 43 DMD/BMD families were recruited. Multiplex PCR was used to analyze 18 exons within hotspots for DMD gene deletions. Multiplex ligation-dependent probe amplification (MLPA) was used to detect potential deletions and duplications of DMD gene for 43 patients and 36 females from 32 families. Prenatal diagnosis was performed for 27 families.</p><p><b>RESULTS</b>Deletional mutations were detected in 26 patients with multiplex PCR. In addition, MLPA has detected 3 deletions and 6 duplicational mutations, and the ranges of mutations were all determined. Among 36 female members, 18 were determined as carriers of deletional mutations, 10 were excluded as mutation carriers. The status of remaining 8 could not be determined. For prenatal diagnosis, 3 out of 18 male fetuses were diagnosed as patients and 1 female fetus was identified as carrier.</p><p><b>CONCLUSION</b>MLPA is an accurate and reliable method for detecting deletional/duplicational mutations of DMD gene as well as for prenatal diagnosis and detection of female carriers.</p>

Relationship between TIM-4 polymorphism and childhood asthma / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To elucidate whether the polymorphism of asthma immune regulator gene TIM-4 is associated with the risk of childhood allergic asthma in the southwest region of China.</p><p><b>METHODS</b>TIM-4 gene promoter region RS6882076 and intron RS4704727 were studied. PCR-RFLP was used to test the genotypes of two polymorphism loci among 579 cases (average 7.2 years old) of asthma and 524 controls (average 7.6 years old) in a case-control study.</p><p><b>RESULTS</b>There were significant differences in the frequency of gene types at RS4704727 site between the asthma and the control groups (P<0.01). The results of PCR-RFLP showed that the polyporphisms of RS6882076 and RS4704727 in TIM-4 gene were present in this study population. The frequency of T allele at the RS4704727 site in the asthma group was significantly lower than that in the control group (OR=1.603; 95%CI 1.304-1.971; P<0.01). There were no significant differences in the frequencies of gene types and allele at RS6882076 site between the two groups (P>0.05).</p><p><b>CONCLUSIONS</b>RS4704727 polymorphism of TIM-4 gene may be associated with childhood asthma, providing a better understanding of the pathogenesis of childhood asthma in the Southwest region of China.</p>

Molecular genetic study of MECP2 gene for a patient with typical Rett syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To provide genetic diagnosis and counseling for a 2-year-old girl with typical Rett syndrome through analyzing the methyl-CpG binding protein 2 (MECP2) gene.</p><p><b>METHODS</b>Potential mutation of the MECP2 gene was screened by DNA sequencing and multiplex ligation-dependent probe amplification (MLPA) analysis of members of the family as well as normal controls. Lymphocyte culture for karyotype analysis was carried out for the patient to exclude chromosomal abnormalities.</p><p><b>RESULTS</b>The karyotype of the girl was normal. No variation of the MECP2 gene was detected in the patient by direct sequencing. A heterozygosis variation, c.1072G>A in exon 4 of the MECP2 gene was detected in a normal female control, which was not found in other controls. The son and daughter of the female control were respectively heterozygous and homozygous carriers of the same mutation. By MLPA analysis, a heterozygosis deletion of exon 3 and part of exon 4 was detected in the patient. cDNA amplification and sequencing confirmed the presence of a 1176 bp deletion (c.27-1202del1176). The same deletion was not detected in the parents.</p><p><b>CONCLUSION</b>A large deletion in MECP2 gene was detected with MLPA in a patient featuring typical Rett syndrome. The same deletion was missed by sequencing analysis. With cDNA sequencing, the breakage point of the mutation can be mapped precisely.</p>