Phenotypic and genetic analysis of a child featuring multiple malformations due to copy number variation on chromosome 5 / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the origin of chromosomal aberration for a child featuring multiple malformation, and to correlate the genotype with phenotype.</p><p><b>METHODS</b>Routine G-banding was performed to analyze the karyotype of the patient and her parents, and array comparative genomic hybridization (array CGH) was used for fine mapping of the aberrant region.</p><p><b>RESULTS</b>The karyotype of the child was ascertained as 46,XY. Array CGH has mapped a 14.21 Mb deletion to 5p15.2p15.33, and a very small 3.67 Mb duplication to 5q35.3. The patient has presented features such as mental retardation, heart defect, low-set ears, hypertelorism and down-slanting palpebral fissures.</p><p><b>CONCLUSION</b>Chromosome 5 copy number variation can cause multiple malformation. In contrast to routine karyotype analysis, array CGH can map aberrant region with much higher resolution and accuracy.</p>

A novel splicing mutation in intron 2 of DSPP gene in a family with dentinogenesis imperfecta type Ⅱ / 临床检验杂志

Objective To report a familial dentinogenesis imperfecta type Ⅱ (DGI type Ⅱ) with a novel splicing mutation in DSPP (dentin sialophosphoprotein) gene.Methods Based on the result of linkage analysis performed previously to map the candidate gene DSPP in the family, the promoter,the first four exons and exon-intron boundaries of DSPP were directly sequenced for the members of the DGI type Ⅱ family. Denaturing high performance liquid chromatography (DHPLC) analysis was performed to confirm the results of sequencing.Results A novel splicing mutation of 23 bp deletion in intron 2 of DSPP gene was identified by DNA sequence analysis. The mutation changed acceptor site sequence from CAG to AAG, and might result in functional abolition of possible branch point site in intron 2. DHPLC result was consistent with that of sequencing. The mutation may be identified in all affected individuals, but not found in normal members of the family and 50 controls.Conclusion These results suggest the deleted mutation of DSPP gene causes DGI type Ⅱ in the family. The mutation has not been reported before.

A novel RNA-splicing mutation in COL1A1 gene causing osteogenesis imperfecta typeⅠin a Chinese family / 医学研究生学报

A) in COL1A1 gene resulting in OI in a Chinese family. The detailed molecular and clinical features will be useful for extending the evidence for genetic and phenotypic heterogeneity in OI and exploring the phenotype-genotype correlations in OI.

An infertile 45,X male carrying an unbalanced(Y,13) translocation:A clinical cytogenetic and molecular study / 医学研究生学报

Objective: To report a case of azoospermia with a karyotype of 45,X,der(Y)t(Y;13)(q11.2;q12),-13,accompanied with slight bilateral gynecomastia and multiple nodules.Methods: The karyotype was identified by karyotyping and FISH,and the breakpoints of the Y chromosome and the copy number of the BRCA2 gene in 13q12 determined by PCR-STS and DNA polymorphic analysis.The testis and nodule tissues of the patient were obtained for biopsy.Results: FISH confirmed SRY and centromere of the Y chromosome on the questionable 13 chromosome and the karyotype to be 45,X,der(Y)t(Y;13)(q11.1;q12),-13.ish der(Y)(SRY+,DYZ3+,wcp13+).PCR-STS showed the deletion of regions AZFa,b and C,with a breakpoint located inYq11.1 below sY82.No deletion of the BRCA2 gene was observed.The patient was diagnosed with Sertoli cell-only syndrome by testicular biopsy and with angiolipomata by pathological examination of the nodule tissue.Conclusion: The patient's phenotype of complete masculinization could be attributed to presence of the SRY gene,and his azoospermia with small testis to the absence of a fragment from Yq11.1 to Yqter.However,the molecular mechanism of angiolipoma remains unknown.

Prenatal molecular diagnosis of two pregnancies in familial G504S mutation of COL2A1 gene resulting spondylepiphyseal dysplasia congenita / 临床检验杂志

Objective To report the prenatal molecular diagnosis for two gravida in a family with spondylepiphyseal dysplasia congenita(SEDC)caused by G504S mutation of COL2A1 gene.Methods DNA of the two fetuses was extracted from amniotic fluid at the 19+3 and 18+6 weeks of gestation respectively.Direct sequencing of two samples were performed after amplifying exon 23 of COL2A1 containing the potential mutation.The femur length and biparietal diameter of the first fetus were measured by sonographic scans every two weeks from 17+3 weeks to 27+3 weeks of gestation,and for the second fetus these parameters were measured from 16+1 to 19+1 weeks of gestation.Results Sequncing analysis revealed the first fetus and his mother presented the same mutation which is specifically associated with SEDC,but the second fetus did not show the mutation of COL2A1 gene.Biparietal diameters of the both fetuses were appropriate for gestational age.Femur length of the second fetus was normal for gestational age but that of the first fetus was shortened evidently after the 23 week of gestation.The parents of the first fetus determined to terminate the pregnancy.A medical termination was carried out at 27+5 weeks of gestation and a male fetus with a relatively large head and short limbs was delivered.The radiological findings of the fetus were consistent with SEDC including generalized platy spondesand shortened long bones.Conclusions Prenatal molecular diagnosis is important for the fetus with risk of SEDC and useful for genetic counseling.Genotype of fetus with risk of SEDC can be identified before sonographic scan.Molecular genetic analysis in conjunction with sonographic monitoring was helpful in prenatal diagnosis of SEDC.