To define whether alcohol drinking provides a risk for Leber's hereditary optic neuropathy (LHON), the genotypes of low K(m) aldehyde dehydrogenase (ALDH2) and alcohol dehydrogenase type 2 (ADH2), major enzymes involving the alcohol metabolism, were examined in 29 unrelated Japanese patients with LHON associated with mitochondrial DNA 11778 mutation, 24 unrelated asymptomatic carriers with the mutation and 57 normal controls without the mutation. PCR-restriction detection revealed three genotypes of ALDH2 and ADH2. The allele frequencies of either enzyme in LHON patients, asymptomatic carriers, or both, did not differ from those in normal controls. There is no association between LHON and genotypes of alcohol-metabolizing enzymes. However, six of the LHON patients had frequent alcohol consumption, while none of the asymptomatic carriers claimed frequent drinking habit. Thus, we could not make a denial of drinking effects on optic nerve damage in LHON.
The author states in the introduction to the first edition, that he "believe(s) that it should be a useful book for medical students who wishes to become familiar with recent ideas and techniques in molecular biology to help in understanding further advances when they arrive.It will also be of use to honours and graduate students in genetics, biochemistry and those who would not necessarily regard the topics discussed here as their major interests in these subjects."It starts from chemical structure of DNA, proceeds into methodology, prokaryotic and eukaryotic gene expression, and extends its description to oncogene, immune system, etc.This book, therefore, is rather a miniaturized version of the renowned textbooks such as J.D. Watson's "Molecular Biology of the Cell" than what one might imagine from the title.Our knowledge in this field is expanding ever so rapidly, that any textbook of this comprehensiveness "will certainly be out of date before the writing is finished, let alone published.".Yet, this book is doing reasonably well to catch up recent findings in some topics, such as eukaryotic transcription and bacterial replication.Looking through the chapters, I noticed total lack of basic description of protein structure which is necessary for the claimed readership.In "1.6 Protein binds to DNA," it says "Three main types of domain structures are involved ..." without explaining what is domain structure.The chapter, "12.Some gene families" suddenly starts by describing collagen.Isn't the concept of gene family the group of genes that encodes proteins of related structure?Descriptions in 12.8 (Polyproteins are proteolytically processed to yield the active hormones) are certainly misplaced.Turning the pages, I found surprising density of inappropriate or in many cases erroneous sentences or figures.To name a few, 1. p. 7. Fig. 1.5.None of the drawings show supercoiled DNA. 2. p. 1 I.Many C2H2 zinc finger proteins are found in many organisms including human, and "fungal proteins that controls the synthesis of certain small
We report here on a Japanese male infant with megalocornea-mental retardation (MMR) syndrome. He had megalocornea (corneal diameter: 13 mm) without glaucoma, developmental retardation, hypotonia, frontal bossing, high-arched palate, carp-like mouth, micrognathia, and delayed myelination. He seems to be included in Verloes type of the MMR syndrome.
To establish a genotypic database for dinucleotide repeat marker loci in the Japanese population, we determined allelic frequencies of 12 such markers on chromosome 13 and compared them with data from Caucasians in the GDB archive. The average heterozygosity (79%) for the 12 loci was the same for the two populations. However, allelic distributions at two of the marker loci were quite different. These data will be useful for disease studies in the Japanese population that involve linkage or sibship-pair analyses, or association studies.
We reported on two patients with ade novo marker chromosome of which the origins were successfully identified by FISH using microdissected probes. These probes were established by microdis-sections of extra chromosomal segments from Carnoy-fixed cells stored at −20°C for several years. Using these probes, we could verify partial 1q32 trisomy in a patient with 17p+ as well as partial 16q2 trisomy in another patient with 4p+.
We report on a sporadic case satisfied with a proposed diagnostic criteria for Cohen syndrome. This 10 year-old Japanese boy had truncal obesity, short stature, mild mental retardation, hypotonia, maxillary hypoplasia, micrognathia, narrow hands and feet, high-arched palate, prominent upper central incisors, high nasal bridge, but no pigmentary retinopathy. Autosomal recessive manner of inheritance was suggested by the pedigree.
The tumor necrosis factor B (TNFB) gene is closely liked with tumor necrosis factor A (TNFA) gene between the HLA-B and C2 genes on chromosome 6p21.3. Several genetic variabilities at the human TNFB loci have been identified, which are the NcoI restriction fragment length polymorphism (RFLP) in the first intron, amino acid substitution at codon 26 of exon 3 and EcoRI RFLP in untranslated exon 4. The NcoI RFLP of TNFB gene gives two allelic fragments of 238/259 bp and 497 bp, corresponding to TNFB*1 and TNFB*2 alleles, respectively. To investigate the frequency of NcoI RFLP in the first intron of TNFB in Koreans and to compare to that of other ethnic population, genomic DNAs were extracted from leukocytes of 305 unrelated healthy Koreans and amplified the first intron of TNFB gene by PCR. The phenotype frequencies of NcoI RFLP such as TNFB* 1/TNFB*1, TNFB*1/TNFB*2 and TNFB*2/TNFB*2 were 8.6% (n = 26), 45.2% (n = 138) and 46.2% (n = 141), respectively. The estimated allele frequencies for TNFB*1 and TNFB*2 were 0.3115 and 0.6885, respectively. The observed and expected frequencies were in good agreement with the Hardy-Weinberg's equilibrium. The heterozygosity revealed 45.2% and the allele frequencies of NcoI RFLP of TNFB in Koreans were observed comparatively similar to those of other ethnic groups.
The transcription factor KBF2 has been characterized as a factor that binds to the NFkB site of mouse major histocompatibility complex (MHC) class I genes and its amino acid sequence has been shown to be identical to those of members of the recombination signalsequence binding protein (RBP-Jk) family. Previous studies by Amakawaet al. (Genomics17, 306–315, 1993) demonstrated that the functional gene is localized at human chromosome 3q25. However, in the present study we showed byin situ hybridization with the functional KBF2/RBPJk cosmid clone that the gene is localized at 9p12-13 and 9q13, namely, at the same loci as pseudogenes that were reported previously (Zhanget al., Jpn J Human Genet39, 391–401, 1994).
Nerve growth factor (NGF) induces neurite outgrowth and promotes survival of embryonic sensory and sympathetic neurons. TRKA, a receptor tyrosine kinase cloned from a human colon cancer was later found to be expressed in the nervous system and phosphorylated in response to NGF. Somatic rearrangement(s) of theTRKA gene (also designatedNTRK1) are responsible for formation of some oncogenes. Genetic defects in TRKA are responsible for a human disorder, congenital insensitivity to pain with anhidrosis (CIPA). We report here isolation and characterization of theTRKA gene which spans at least 23 kb and is split into 17 exons. Exon sizes range from 18 to 394 bp and intron sizes range from 170 bp to at least 3.3 kb. Sizes and boundaries of the exons were determined, and all the splice donor and acceptor sites conformed to the GT/AG rule. Approximately 1.2 kb of the 5′-flanking regions was sequenced, and putative regulatory elements were identified. These results will be useful for studies on the developmental and biological regulation of theTRKA gene and for further characterization of mutations in CIPA patients as well as elucidation of mechanisms responsible for rearrangement(s) observed in human tumors.
Nager acrofacial dysostosis is characterized by radial defect and the facial manifestations like Treacher-Collins syndrome. There are few reports about this syndrome in Japan. We report a typical Japanese Nager syndrome patient. He was complicated with respiratory distress syndrome.
Moyamoya disease is a clinical entity demonstrating a chronic occlusion of the cerebrovascular system. Although some possible etiological factors have been postulated, the etiology of this disease is still unknown. So far, some investigations have suggested the association between moyamoya disease and HLA in the serological typing. However, DNA typing of HLA have not been performed yet. Thus, we performed DNA-typing of HLA in the unrelated Japanese patients with definite moyamoya disease, using the polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) technique. In the total patients,DQB1*0502 had a positive association with the disease. On the other hand,DRB1*0405 andDQB1*0401 showed a negative association. In comparing the early-onset and late-onset groups, two groups did not share the same disease associated alleles at all. Thus, the etiology of moyamoya disease seem to have a genetic background. Furthermore, different genetic factors might also be involved in the difference between the early-onset and late-onset groups.
Germline mutations of the adenomatous polyposis coli (APC) gene have been reported in patients with familial adenomatous polyposis (FAP) and are believed to be an early event in colorectal carcinoma. We report the results of screening for germline mutations of the APC gene in 4 cases of 2 kindreds using non-radioactive PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) analysis. The mutation in kindred 1 was a 4 bp deletion at codon 849 in exon 15, resulting in a frameshift leading to truncation of the APC gene product. In kindred 2, a transversion of C to G at codon 2038 was observed, resulting in an amino acid change from leucine to valine. In this case, it is possible to screen presymptomatic diagnosis easily and quickly by digestion with restriction enzyme EcoNI.
We have developed a fast and comprehensive method to scan for point mutations in a gene on X chromosome. A target region of the gene is first amplified. Then, using the amplified product as a template, PCR is carried out with multiple short-length forward primers arrayed in tandem in the scanned region, and a common reverse primer. The absence of amplified product defines the site of a mutation within a narrow region of the primer recognition site. To evaluate our method, point mutations in exon 12 of the human glucose-6-phosphate dehydrogenase (G6PD) gene were used as a model system. Out of 12 Singaporean G6PD-deficient patients, 6 cases were shown by the method to have a nucleotide change in this exon. Sequence analysis confirmed the presence of a nucleotide change in the region identified by our scanning. Thus, our method is accurate in localizing mutations within a narrow region, and allows large numbers of samples to be handled simultaneously.
The genotypes of the ABO blood group system were investigated in Korean living in Kangwon-Do area by PCR-RFLP analysis of the seven polymorphic nucleotide positions 261, 467, 526, 646, 703, 796 and 803 of the cDNA from A1 transferase. In 253 unrelated Korean individuals, 15 genotypes were found and the allele frequencies of A(Pro), A(Leu), B, O(T) and O(A) were 0.022, 0.209, 0.209, 0.360 and 0.200, respectively, with no deviation from Hardy-Weinberg expectations (x 2=2.145, d.f.=6, 0.90<p<0.95). As for the distribution of allele frequencies, a significant difference was noticed between the Korean and a Japanese (x 2=30.87, d.f.=4, p<0.001) and a German (x 2=127.76, d.f.=4, p<0.001) populations.
An azoospermic male with an unbalanced translocation between the Y chromosome and chromosome 15 was examined in the present study. Testicular biopsy found only Sertoli cells only within the seminiferous tubules of the 35-year-old patient. Chromosome analysis, using the techniques of G and C banding and fluorescent in situ hybridization revealed an abnormal karyotype of 46,XY,der(15)t(Y;15)(q12;p11). Deoxyribonucleic acid (DNA) analysis confirmed the presence of the genes such as DAZ and YRRM1 which are known to control spermatogenesis. The cause of spermatogenetic dysfunction in this particular patient therefore.
Tyrosinase-related oculocutaneous albinism (OCA1), an autosomal recessive inborn error of pigmentation, is caused by the deficiency of tyrosinase. We had previously identified two different mutations of theTYR gene in a four year old Korean male with mild OCA; a P310insC frameshift in exon 2 and an IVS2-7t→a, -10--11deltt splice junction mutation in exon 3. Here we report a prenatal diagnostic study of a subsequent fetus of the above family that was at 25% risk of OCA1. SSCP/heteroduplex screening, restriction enzyme digestion, and allele-specific oligonucleotide hybridization analyses of DNA obtained by chorionic villus sampling indicated that the fetus was a compound heterozygote for the paternal P310insC and the maternal IVS2-7t→a, -10--11deltt mutations. The diagnosis was later confirmed by observation of poorly pigmented irides of the abortus terminated at the 18th week of gestation. This approach provides a fast and reliable method for DNA-based prenatal diagnosis when specific mutations are known in families at high risk of OCA1.
Epidermolytic hyperkeratosis (EHK), or bullous congenital ichthyosiform erythroderma, is characterized by generalized erythroderma, ichthyosiform skin and blistering, and is caused by an aberration of the keratin intermediate filaments. In this study, we examined keratin K10 and 1 gene mutations in a Japanese EHK patient who had severe ichthyosiform erythroderma at birth and developed subsequent blistering. The patient had a G to A transition at codon 156 of the keratin K10 gene, which resulted in an arginine (Arg)→histidine (His) substitution in the helix initiation peptide of the highly-conserved 1A domain in keratin K10. This is the first mutation report of a Japanese patient with EHK, although the position and mode of the mutation identified here did not differ from those in reported Western cases.
