Clinical and genetic analysis of a child with 2q37 deletion syndrome resulting from a translocation involving chromosome satellite / 中华医学遗传学杂志

OBJECTIVE@#To carry out cyto- and molecular genetic testing for a child featuring facial dysmorphism and attention deficit and hyperactive disorder.@*METHODS@#The child was subjected to routine peripheral blood lymphocyte chromosomal karyotyping, fluorescence in situ hybridization (FISH) and single nucleotide polymorphism array (SNP-array) analyses.@*RESULTS@#The child's facial dysmorphism included low-set ears, curly ear auricle, protuberance of eyebrow arch, nostril notch, short and flat philtrum and thin upper lip. SNP-array revealed that he has carried a 4.883 Mb deletion at 2q37. His chromosomal karyotype was ultimately determined as 45, XY, der(2;21) (2pter→ 2q37.3::21p13→ 21p10::20p10→ 20pter), der(20) (21qter→ 21q10::20q10→ 20qter).@*CONCLUSION@#A rare case of 2q37 deletion syndrome involving three chromosomes was discovered. Combined use of various cyto- and molecular genetic techniques is crucial for the diagnosis of chromosomal abnormalities with complex structures.

Analysis of a Chinese pedigree with autosomal dominant Charcot-Marie-Tooth disease type 2A2A / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis of a pedigree affected with peroneal muscular atrophy.@*METHODS@#Neuroelectrophysiological examination and whole exome sequencing were carried out for the proband, a six-year-and-ten-month-old boy. Suspected variant was verified in his family members through Sanger sequencing. Bioinformatic analysis was carried to predict the conservation of amino acid sequence and impact of the variant on the protein structure and function.@*RESULTS@#Electrophysiological examination showed demyelination and axonal changes of motor and sensory nerve fibers. A heterozygous missense c.1066A>G (p. Thr356Ala) variant was found in exon 11 of the MFN2 gene in the proband and his mother, but not in his sister and father. Bioinformatic analysis using PolyPhen-2 and Mutation Taster software predicted the variant to be pathogenic, and that the sequence of variation site was highly conserved among various species. Based no the American College of Medical Genetics and Genomics standards and guidelines, the c.1066A>G (p. Thr356Ala) variant of MFN2 gene was predicted to be likely pathogenic (PS1+ PM2+ PP3+ PP4).@*CONCLUSION@#The heterozygous missense c.1066A>G (p.Thr356Ala) variant of the MFN2 gene probably underlay the disease in the proband, and the results have enabled genetic counseling and prenatal diagnosis for this family.

Analysis of MCCC2 gene variant in a pedigree affected with 3-methylcrotonyl coenzyme A carboxylase deficiency / 中华医学遗传学杂志

OBJECTIVE@#To explore the genetic basis for a child with clinically suspected 3-methylcrotonyl-coenzyme A carboxylase deficiency (MCCD).@*METHODS@#Genomic DNA was extracted from peripheral blood samples of the proband and her parents. Whole exome sequencing was used to screen pathogenic variant in the proband. Suspected variant was verified by Sanger sequencing. Impact of the variant on the structure and function of protein product was analyzed by using bioinformatic software.@*RESULTS@#Sanger sequencing showed that the proband has carried homozygous missense c.1342G>A (p.Gly448Ala) variant of the MCCC2 gene, for which her mother was a heterozygous carrier. The same variant was not detected in her father. The variant was predicted to be pathogenic by PolyPhen-2 and Mutation Taster software, and the site was highly conserved among various species. Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.1342G>A (p.Gly448Ala) variant of MCCC2 gene was predicted to be likely pathogenic(PM2+PP2-PP5).@*CONCLUSION@#The homozygous missense variant of the MCCC2 gene c.1342G>A (p.Gly448Ala) probably underlay the molecular pathogenesis of the proband. Genetic testing has confirmed the clinical diagnosis.

Application of multiple MLL gene rearrangement detection techniques for children with acute mononuclear leukemia / 中华医学遗传学杂志

Objective@#To assess the value of detecting multiple rearrangements of MLL gene in children with acute mononuclear leukemia (AML).@*Methods@#Eighty six children with AML were analyzed by fluorescence in situ hybridization (FISH), chromosomal karyotyping and multiplex reverse transcription-PCR (RT-PCR).@*Results@#Cross signals were detected by FISH in 26 cases, and 30.2% were detected with MLL gene rearrangements. R-band karyotyping analysis revealed 14 translocations with breakages involving 11q23 and 5 other aberrations, which yielded an overall detection rate of 22.1%. Multiple RT-PCR has detected 12 fusion genes produced by the MLL translocation, which yielded a detection rate of 14.0%. A significant difference was found in the detection rate of the three methods (P<0.05).@*Conclusion@#Combined use of FISH, chromosomal karyotyping and multiplex RT-PCR can improve the detection of MLL gene rearrangements and provide important clues for clinical diagnosis, treatment and prognosis of AML.

Application of multiple MLL gene rearrangement detection techniques for children with acute mononuclear leukemia / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of detecting multiple rearrangements of MLL gene in children with acute mononuclear leukemia (AML).@*METHODS@#Eighty six children with AML were analyzed by fluorescence in situ hybridization (FISH), chromosomal karyotyping and multiplex reverse transcription-PCR (RT-PCR).@*RESULTS@#Cross signals were detected by FISH in 26 cases, and 30.2% were detected with MLL gene rearrangements. R-band karyotyping analysis revealed 14 translocations with breakages involving 11q23 and 5 other aberrations, which yielded an overall detection rate of 22.1%. Multiple RT-PCR has detected 12 fusion genes produced by the MLL translocation, which yielded a detection rate of 14.0%. A significant difference was found in the detection rate of the three methods (P< 0.05).@*CONCLUSION@#Combined use of FISH, chromosomal karyotyping and multiplex RT-PCR can improve the detection of MLL gene rearrangements and provide important clues for clinical diagnosis, treatment and prognosis of AML.

Evaluation of CYP2C9 activity in rats: use of tolbutamide alone and in combined with bupropion

A [cocktail] of several probe drugs is often used to evaluate metabolic activity of multiple cytochrome P450 enzymes in one session. Some interactions among probe drugs can appear and may impact the rate of biotransformation of other ones. Our presented work was aimed on the influence of bupropion on cytochrome P450-mediated metabolism of tolbutamide. The biotransformation rates of tolbutamide administered either separately or in combined with bupropion were compared in this study. The results revealed that bupropion had no significant effect on tolbutamide hydroxylation. Thus, due to stability in cytochrome P450 enzyme metabolic activity in the case of combining of two model probe drugs the procedure can show to no extent differential results comparing to the single-marker use