Osamu Samura

Meiotic segregation analysis of a 14;21 Robertsonian translocation carrier by fluorescence in situ hybridization

Abstract. Meiotic segregation of chromosomes 14 and 21 in sperm from a 14;21 Robertsonian translocation carrier was analyzed with dual-color FISH using two locus-specific DNA probes (Tel 14q and LSI 21). The frequency of normal or chromosomally balanced sperm, resulting from alternate segregation, was 88.42%. The frequency of unbalanced sperm, resulting from adjacent segregation, was 11.25%. These observed frequencies deviated significantly from the theoretical frequencies (33.33% and 66.67%, respectively) based on random chromosome segregation, with sperm resulting from alternate segregation being preferentially produced in the translocation carrier. With respect to the chromosomally unbalanced sperm, the frequency of 21q disomic sperm was 2.45%, which is in agreement with the frequencies of unbalanced fetuses or offspring at the time of amniocentesis or at term (0–4.3%) reported by others. Although the frequency of 14 or 21 nullisomic sperm should be theoretically equal to that of 14q or 21q disomic sperm in both the carrier and controls, the frequency of nullisomic sperm was significantly higher than that of disomic sperm in the carrier (P=0.0009 for chromosome 14, P<0.0001 for chromosome 21) but not in the controls (P=0.091 for chromosome 14, P=0.74 for chromosome 21). This evidence suggests the occurrence of maturation arrest during spermatogenesis of the carrier.

Blue rubber bleb nevus syndrome: Report of a patient with hemangiomas of the vaginal portion of the cervix appearing during pregnancy

Blue rubber bleb nevus syndrome (BRBNS) is a rare disorder showing venous malformations in the skin and gastrointestinal tract, and other internal organs. We encountered a patient with BRBNS in whom hemangiomas of the uterine cervix appeared during pregnancy. This was apparently the first reported occurrence. To avoid unexpected bleeding from hemangiomas, patients with BRBNS should be examined repeatedly for hemangiomas of the birth canal, and special care should be taken in deciding the mode of delivery.

Detection of chromosomal abnormalities in uterine leiomyoma using conventional cytogenetic method and interphase fluorescence in situ hybridization

Seventy-nine uterine leiomyomas were examined using a conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal abnormalities of chromosome 12. Nine (17.6%) of 51 tumor samples examined showed chromosomal abnormalities by conventional cytogenetic analysis. Rearrangements of chromosome 12 were detected in two tumors. Other tumors showed abnormalities affecting chromosomes 1, 4, 6, 7, 10, 13, 14, and 22. For FISH, the whole-chromosome painting probe and the D12Z3 probe specific for the centromeric region were used to detect structural and numerical abnormalities of chromosome 12. Of forty-one tumor samples, six showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the tumors with structural aberrations identified by FISH, two had normal karyotypes, two showed structural rearrangements of chromosome 12 cytogenetically, and two could not be analyzed because of an insufficient number of metaphases. There were no correlations between the cytogenetic data and clinical parameters. The results indicate that chromosomal abnormalities are important in the biology of at least some types of uterine leiomyomas, and that FISH is a useful complement to conventional cytogenetic analysis in the study of solid tumors.

Microarray and FISH-based genotype-phenotype analysis of 22 Japanese patients with Wolf-Hirschhorn syndrome.

Wolf–Hirschhorn syndrome (WHS) is a contiguous gene deletion syndrome of the distal 4p chromosome, characterized by craniofacial features, growth impairment, intellectual disability, and seizures. Although genotype–phenotype correlation studies have previously been published, several important issues remain to be elucidated including seizure severity. We present detailed clinical and molecular‐cytogenetic findings from a microarray and fluorescence in situ hybridization (FISH)‐based genotype–phenotype analysis of 22 Japanese WHS patients, the first large non‐Western series. 4p deletions were terminal in 20 patients and interstitial in two, with deletion sizes ranging from 2.06 to 29.42 Mb. The new Wolf–Hirschhorn syndrome critical region (WHSCR2) was deleted in all cases, and duplication of other chromosomal regions occurred in four. Complex mosaicism was identified in two cases: two different 4p terminal deletions; a simple 4p terminal deletion and an unbalanced translocation with the same 4p breakpoint. Seizures began in infancy in 33% (2/6) of cases with small (<6 Mb) deletions and in 86% (12/14) of cases with larger deletions (>6 Mb). Status epilepticus occurred in 17% (1/6) with small deletions and in 87% (13/15) with larger deletions. Renal hypoplasia or dysplasia and structural ocular anomalies were more prevalent in those with larger deletions. A new susceptible region for seizure occurrence is suggested between 0.76 and 1.3 Mb from 4pter, encompassing CTBP1 and CPLX1, and distal to the previously‐supposed candidate gene LETM1. The usefulness of bromide therapy for seizures and additional clinical features including hypercholesterolemia are also described.

Functional disomy for Xq22-q23 in a girl with complex rearrangements of chromosomes 3 and X.

A 5‐year‐old girl with developmental and growth retardation is reported with complex chromosome rearrangements consisting of a partial Xq deletion and an abnormal chromosome 3 with multiple breakpoints. GTG‐banding, and multiplex and conventional FISH studies showed that a 6.6‐Mb Xq22‐q23 segment was inserted into 3q, in addition to three intrachromosomal insertions in chromosome 3. Her karyotype was thus interpreted as 46,X,der(X)(Xpter→Xq22::Xq23→Xqter),der(3)(3pter→3p26::3p12→3q25.3::3p12→3p26::Xq22→Xq23::3q25.3→3qter). Replication R‐banding study showed that the der(X) was inactivated in all blood lymphocytes analyzed. Methylation‐specific PCR at the androgen receptor gene (HUMARA) locus at Xq11‐q12 showed a skewed inactivation pattern with the active/inactive X chromosome ratio of 92/8. These data indicated the presence, in the majority of cells, of a functioning Xq22‐q23 segment in both the normal X and the der(3) chromosomes. Her growth retardation, developmental delay, and other minor anomalies were most likely caused by dosage effects of the genes in the functionally disomic Xq22‐q23 region. Despite the presence of two active copies of the proteolipid protein 1 gene (PLP1), she did not show the symptoms of Pelizaeus‐Merzbacher disease, a subset of which has been known to be caused by the duplication of PLP1.

Detection of chromosomal abnormalities of chromosome 12 in uterine leiomyoma using fluorescence in situ hybridization

SummaryFifty uterine leiomyomas were examined using conventional cytogenetic method and fluorescence in situ hybridization (FISH) for detection of chromosomal, abnormalities of chromosome 12. Of the 50 tumors, nine were examined using FISH on the non-cultured samples. Two (4.0%) of 50 tumor samples examined showed chromosomal abnormalities of chromosome 12 by the conventional cytogenetic analysis. For FISH, the whole-chromosome painting probe and D12Z3 probe specific for the centromeric region were used. Of the 50 cultured samples, 10 showed structural aberrations and four showed numerical aberrations of chromosome 12 by FISH analysis. Of the nine non-cultured samples, four showed structural abnormalities of chromosome 12, all of which also showed structural abnormalities of chromosome 12 on the cultured samples. These results indicate that chromosomal abnormalities of chromosome 12 are important in the biology of at least some types of uterine leiomyoma, and that FISH is a useful complement to the conventional cytogenetic analysis in the study of solid tumors.

A Phenotypically Normal Liveborn Male after Prenatal Diagnosis of Trisomy 20 Mosaicism

We report on a case of prenatally diagnosed trisomy 20 mosaicism. Conventional cytogenetic analysis and fluorescence in situ hybridization (FISH) using a chromosome 20 specific probe were performed on the lymphocytes and extra‐embryonic tissues after birth. All of them revealed normal karyotypes. The baby is developing normally at the age of 2 years.