Ikuko Kondo

Establishment of a New Prostatic Carcinoma Cell Line (TSU-PR1)

A new epithelial cell line, TSU-Pr1, from a human prostatic adenocarcinoma metastatic to lymph node has been established in long term tissue culture. The cultured cells show loss of contact inhibition, rapid growth in vitro and growth in athymic nude mice. Karyotypic analysis demonstrated an aneuploid karyotype with a modal chromosome number of 80 including a Y-chromosome and at least 10 marker chromosomes. The cells produced only a small amount of prostatic acid phosphatase, and heterotransplanted tumors did not have nuclear androgen receptors.

Molecular and clinical characterization of cardio-facio-cutaneous (CFC) syndrome: overlapping clinical manifestations with Costello syndrome.

Cardio‐facio‐cutaneous (CFC) syndrome is a multiple congenital anomaly/mental retardation syndrome characterized by heart defects, a distinctive facial appearance, ectodermal abnormalities and mental retardation. Clinically, it overlaps with both Noonan syndrome and Costello syndrome, which are caused by mutations in two genes, PTPN11 and HRAS, respectively. Recently, we identified mutations in KRAS and BRAF in 19 of 43 individuals with CFC syndrome, suggesting that dysregulation of the RAS/RAF/MEK/ERK pathway is a molecular basis for CFC syndrome. The purpose of this study was to perform comprehensive mutation analysis in 56 patients with CFC syndrome and to investigate genotype–phenotype correlation. We analyzed KRAS, BRAF, and MAP2K1/2 (MEK1/2) in 13 new CFC patients and identified five BRAF and one MAP2K1 mutations in nine patients. We detected one MAP2K1 mutation in three patients and four new MAP2K2 mutations in four patients out of 24 patients without KRAS or BRAF mutations in the previous study [Niihori et al., 2006 ]. No mutations were identified in MAPK3/1 (ERK1/2) in 21 patients without any mutations. In total, 35 of 56 (62.5%) patients with CFC syndrome had mutations (3 in KRAS, 24 in BRAF, and 8 in MAP2K1/2). No significant differences in clinical manifestations were found among 3 KRAS‐positive patients, 16 BRAF‐positive patients, and 6 MAP2K1/2‐positive patients. Wrinkled palms and soles, hyperpigmentation and joint hyperextension, which have been commonly reported in Costello syndrome but not in CFC syndrome, were observed in 30–40% of the mutation‐positive CFC patients, suggesting a significant clinical overlap between these two syndromes.

Evidence that poor metabolizers of (S)-mephenytoin could be identified by haplotypes of CYP2C19 in Japanese.

(S)-Mephenytoin is metabolized by CYP2C19. The purpose of this study was to examine availability of phenotyping of poor metabolizers (PMs) of (S)-mephenytoin by polymerase chain reaction (PCR)/restriction enzyme genotyping of CYP2C19 in a Japanese population. We genotyped 217 unrelated healthy Japanese for functionally defective alleles, CYP2C19m1 and CYP2C19m2. The frequencies of the wild type(wm1) and CYP2C19m1 were 0.726 and 0.274, and the wild type(wm2) and CYP2C19m2 were 0.892 and 0.108 respectively. Although the observed numbers of three genotypes were very similar to those estimated according to the Hardy-Weinberg equilibrium for each defect, CYP2C19m2 was not detected in m1 homozygotes, and CYP2C19m1 was not detected in m2 homozygotes. Two defects were inherited separately in four families indicating CYP2C19m1 and m2 segregate independently at the same gene locus. Based on these data, we calculated the haplotype frequencies of wm1-wm2, CYP2C19m1-wm2 and wm1-CYP2C19m2 to be 0.618, 0.274 and 0.108 respectively. Frequencies of homozygotes for CYP2C19m1 and CYP2C19m2 and compound heterozygotes associated with the PM phenotype, were calculated to be 7.5, 1.2 and 5.9% respectively. In total, 14.6% of Japanese are estimated to be PMs. No significant difference was observed between the frequencies of PMs calculated from our results and that identified by urinary S/R ratio (18%) (p > 0.05, chi 2 = 0.545, fd = 1). Our data indicate that Japanese PMs of (S)-mephenytoin could be identified by PCR-based genotyping of CYP2C19.

Trisomy 12p syndrome

SummaryThe first case of trisomy of probable 12p mosaicism originated de novo is presented. Comparison of the clinical findings of this patient with those of previously described cases of 12p trisomy derived from translocated chromosomes indicates that the symptoms of 12p trisomy are: (1) normal birth weight and physical development, (2) severe psychomotor retardation and generalized hypotonia, (3) peculiarly round face with prominent cheeks, hypertelorism, epicanthus, broad, flat nasal bridge, short nose with anteverted nostrils, large philtrum, broad, prominent lower lip, and (4) poly(syn)dactyly of feet.

Frequency of the fragile X syndrome in Japanese mentally retarded males

SummaryAmong 243 institutionalized mentally retarded males in Japan, 13 patients (5.3%) with the fre(X)(q27) from nine families were detected. These 13 patients accounted for 8.6% of 152 male inmates with unknown causes of mental retardation in the population. One out of nine pedigrees had an apparently unaffected male transmitter of this disorder. Our data agree with the frequencies of the fra(X) syndrome in various retarded populations, most of which were Caucasians, suggesting that the prevalence of the fra(X) syndrome in Japanese is not significantly different from those in Causasians.

Mutation analysis of the SHOC2 gene in Noonan-like syndrome and in hematologic malignancies.

Noonan syndrome is an autosomal dominant disease characterized by dysmorphic features, webbed neck, cardiac anomalies, short stature and cryptorchidism. It shows phenotypic overlap with Costello syndrome and cardio-facio-cutaneous (CFC) syndrome. Noonan syndrome and related disorders are caused by germline mutations in genes encoding molecules in the RAS/MAPK pathway. Recently, a gain-of-function mutation in SHOC2, p.S2G, has been identified as causative for a type of Noonan-like syndrome characterized by the presence of loose anagen hair. In order to understand the contribution of SHOC2 mutations to the clinical manifestations of Noonan syndrome and related disorders, we analyzed SHOC2 in 92 patients with Noonan syndrome and related disorders who did not exhibit PTPN11, KRAS, HRAS, BRAF, MAP2K1/2, SOS1 or RAF1 mutations. We found the previously identified p.S2G mutation in eight of our patients. We developed a rapid detection system to identify the p.S2G mutation using melting curve analysis, which will be a useful tool to screen for the apparently common mutation. All the patients with the p.S2G mutation showed short stature, sparse hair and atopic skin. Six of the mutation-positive patients showed severe mental retardation and easily pluckable hair, and one showed leukocytosis. No SHOC2 mutations were identified in leukemia cells from 82 leukemia patients. These results suggest that clinical manifestations in SHOC2 mutation-positive patients partially overlap with those in patients with typical Noonan or CFC syndrome and show that easily pluckable/loose anagen hair is distinctive in SHOC2 mutation-positive patients.

Mutagenicity of cyclosporine. Induction of sister chromatid exchange in human cells

To examine whether cyclosporine (CsA) has mutagenic potential against human cells, we analyzed sister chromatid exchange (SCE) induction by CsA using human lymphocytes in vitro. SCE frequencies increased significantly in the lymphocytes treated with 1 microgram/ml and 5 micrograms/ml CsA, though the frequencies seemed to be less than one hundredth of those induced by mitomycin C (MMC). The value of induced SCE depended on CsA concentration. This result indicates that CsA has SCE inducibility. The data also suggest that CsA has a mutagenic effect on human lymphocytes.

Mosaicism for del(17) (p11.2p11.2) underlying the Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a multiple congenital anomalies/mental retardation syndrome associated with deletion of band p11.2 of chromosome 17. The deletion is typically detected by high-resolution cytogenetic analysis of chromosomes from peripheral lymphocytes. Fluorescence in situ hybridization (FISH) has been previously used to rule out apparent mosaicism for del(17)(p11.2p11.2) indicated by routine cytogenetics. We now report mosaicism for del(17)(p11.2p11.2) in a child with SMS. The mosaicism had gone undetected during previous routine cytogenetic analysis. FISH analysis of peripheral lymphocytes as well as immortalized lymphoblasts using markers from 17p11.2 revealed that approximately 60% of cells carried the deletion. To our knowledge, this is the first case of SMS associated with mosaicism for del(17)(p11.2p11.2).

Familial retinoblastoma (mother and son) with 13q14 deletion

SummaryWe present here the first familial cases (a mother and son) of dominantly inherited retinoblastoma with a 13q14 deletion [46,XY or XX,del(13)(q14.1q21.2)]. Their esterase D activities in red blood cells were as low as 50% of the normal control and the haplotype of esterase D was a type 1-0 in the mother and a type 2-0 in the son. They had peculiar facies characterized by a high forehead, low and broad nasal root, a short and bulbous nose, a long philtrum, and open mouth with a thin upper lip, and prominent earlobes. Chromosome and esterase D analysis should be performed in patients with retinoblastoma even if retinoblastoma seems to be transmitted through an autosomal dominant inheritance. This family indicates that one of the causes of dominantly inherited retinoblastoma is a chromosome deletion of part of the 13q14 band whether it is detectable by chromosome analysis or not.

Frequencies of apolipoproteins E5 and E7 in apparently healthy Japanese

SummaryHuman apolipoprotein (apo) E plays an important role in the metabolism of cholesterol and other lipids. Apo E5 and apo E7 are genetic variants of apo E and have been detected in about 5% of Japanese patients with hyperlipidemia and ischemic heart disease. The existence of apo E5 and apo E7, however, had not been reported in apparently healthy individuals except for a few family members of the patients with apo E5 or apo E7. It has been suggested that apo E5 and apo E7 are closely related to the development of atherosclerosis. The purpose of this study is to investigate the frequency of apo E5 and apo E7 in apparently healthy Japanese and to analyze serum lipid levels of the individuals with apo E5 or apo E7.The apo E phenotypes of 197 apparently healthy Japanese adults were determined by two-dimensional gel electrophoresis. The gene frequencies of apo E were: ɛ3, 0.843; ɛ4,0.112; ɛ2, 0.038; ɛ5, 0.006; ɛ7, 0.00035. Three out of 187 subjects (1.5%) were found to have apo E5 or apo E7 in heterozygous state. Two of them were heterozygous with apo E3 (apo E3/5 and apo E3/7) and the both had normal serum lipid levels, though they were more than 50 years old. The other individual was heterozygous with apo E2 (apo E2/5) and had mild hypertriglyceridemia. As to myocardial infarction, angina pectoris and cerebral infarction, no clinically abnormal findings were detected in all the three individuals with apo E5 or apo E7.The data suggest that the frequency of the individuals with apo E5 or apo E7 is of the order of 1% and much higher than that of the homozygotes with apo E2/2 in Japanese. The data also indicate that further genetic, epidemiologic and clinical studies are required to determine whether ɛ5 and ɛ7 act as a dominant major gene, as a recessive major gene, or as one of polymeric genes, in predisposing one to hyperlipidemia and atherosclerosis.