OBJECTIVETo analyze a case of supernumerary marker chromosome (SMC) with combined genetic techniques and explore its correlation with the clinical phenotype.

METHODSThe SMC was analyzed with G-banded karyotyping, multiplex ligation dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH), and single nucleotide polymorphism array (SNP-array).

RESULTSG-banding analysis indicated that the patient has a karyotype of 47,XX,+mar. MLPA showed that there were duplications of proximal 15q. FISH assay using D15Z4 probes indicated that the SMC was a pseudodicentric chromosome derived from chromosome 15. And SNP-array revealed that there were two extra copies of 15q11-13 region spanning from locus 20 161 372 to 29 071 810.

CONCLUSIONThe duplication of Prader-Willi/Angelman syndrome critical region probably underlies the abnormal phenotype of the inv dup(15) case with a BP3:BP3 rearrangement.

Adult ; Chromosome Banding ; Chromosome Disorders ; genetics ; Chromosomes, Human, Pair 15 ; genetics ; Female ; Gene Rearrangement ; Humans ; In Situ Hybridization, Fluorescence ; Karyotyping

OBJECTIVETo analyze mutation of adenomatous polyposis coli (APC) gene in a family affected with familial adenomatous polyposis.

METHODSThe diagnosis was made based on clinical manifestations, family history, presence of numerous polyps in the colon as well as pathological examination. Peripheral blood samples were collected, and genomic DNA was extracted. Potential mutation of the APC gene was detected by polymerase chain reaction (PCR) and DNA sequencing. After finding the mutation in the proband, the same mutation was screened among other family members. The mutation was also confirmed with PCR-restriction fragment length polymorphism (RFLP), with which 100 unrelated healthy controls were examined.

RESULTSA novel heterozygous nonsense mutation c.2891T>G (L964X) of the APC gene was identified in this pedigree. The mutation has led to premature termination of translation. The same mutation was not detected among the 100 healthy controls.

CONCLUSIONThe c.2891T>G (L964X) of the APC gene probably underlies the familial adenomatous polyposis in this pedigree. The combined DNA sequencing and PCR-RFLP method is efficient and accurate for the diagnosis.

Adenomatous Polyposis Coli ; diagnosis ; genetics ; Adenomatous Polyposis Coli Protein ; genetics ; Adult ; Base Sequence ; Child, Preschool ; Colorectal Neoplasms ; diagnosis ; genetics ; Female ; Humans ; Male ; Molecular Sequence Data ; Mutation, Missense ; Pedigree ; Point Mutation ; Young Adult

OBJECTIVETo delineate the origins of small supernumerary marker chromosomes (sSMCs) identified in 4 infertile males.

METHODSThe sSMCs were analyzed with combined G-banding, N-banding, multiplex ligation-dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH) and single nucleotide polymorphisms array (SNP-array) techniques.

RESULTSG-banding analysis has suggested a 46,X,-Y,+mar karyotype in all of the 4 cases. N-banding revealed that all of the sSMCs have possessed two satellites located on both sides. By MLPA, 1 patient showed copy number gains for 15q11.2 region. SNP-array analysis suggested that all had duplication for 15q11.1-q11.2 region, spanning 3.06 Mb, 0.9118 Mb, 1.728 Mb and 0.287 Mb, respectively. By FISH analysis, all of the sSMCs showed two hybridization signals, indicating that they were dicentric chromosomes.

CONCLUSIONIn all of the four cases, the marker chromosomes have derived from chromosome 15 and were bisatellited and dicentric, which gave rise to a karyotype of 47,XY,+ish,inv dup(15)(q11)(D15Z4++). sSMC 15q11 therefore may be a major cause for male infertility.

Adult ; Chromosome Banding ; Chromosomes, Human, Pair 15 ; genetics ; Female ; Genetic Markers ; Humans ; Infertility, Male ; genetics ; Male ; Pregnancy