Abstracts of the 40Th Annual Meeting of the JAPAN SOCIETY of HUMAN GENETICS
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Abstracts of the 40th Annual Meeting of THE JAPAN SOCIETY OF HUMAN GENETICS September 20-22, 1995, Kumamoto, Japan President." Ichiro MATSUDA, M.D., D.M.Sc. (Professor, Department of Pediatrics, Kumamoto University School of Medicine, Kumamoto) Abstracts of 40th Annual Meeting 15 Plenary Lectures PL-1 TOWARDS THE SECOND PHASE OF THE HUMAN GENOME PROJECT. Y0shiyuki SAKAKI(Human Genome Center, Inst. of Med.Sci., Univ. of Tokyo, Tokyo) The Human Genome Project (HGP), started about five years ago as an international project, has made remarkable progress. Major achievements are (1) a fine genetic (about lcM interval) and a back-bone YAC contig maps of the human genome, (2) discovery of various disease genes including those for cancer and neurological disorders, (3) large collection of (partial) cDNA sequences, (4) extensive sequence analysis of several organisms' genomes including those of yeast and nematode, (5) establishment of databases and computer networks for HGP. Under those progress, HGP is now shifting to the second phase, in which major goals are more fine and ultimately sequence analysis of the human genome, extensive analysis of the genes related to common diseases, complete cDNA catalogues, functional analysis of various organisms' genomes on the basis of their complete nucleotide sequences, and development of bioinformatics for relating sequence information to biological functions. Various new activities for the second phase including new sequence centers are now under way. PL-2 EPISODIC DIVERSIFICATION OF GENE FAMILIES AND RELATIONSHIP WITH ORGANISMAL EVOLUTION. Taka~hi MIYATA, Na0yuki IWABE, Kei- ichi KUMA, Naruo NIKOH, Hiroshi SUGA (Dept. Biophys., Kyoto Univ., Kyoto) To know a possible relationship between organismal and molecular evo- lution, a molecular phylogenetic analysis was carried out for 25 different gene families. Based on the inferred phylogenetic trees, the pattern of gene diversification was examined by taking special notice of functional difference, tissue distribution and intracellular localization of the members. Vertebrate tissue-specific isoforms, a group of members carrying virtually identical func- tion to one another, but differing in tissue distribution, have been shown to had undergone extensive gene duplications and rapid accumulation of amino acid substitutions in the early evolution of chordates before the sepa- ration of fishes and tetrapods. In contrast, in the later period the genetic variations are relatively low. The rapid and episodic pattern of evolution observed at the molecular level is correlated well with that of tissue evolu- tion, and thus evolution at the two levels may be related. A similar phyloge- netic analysis of Ca 2+ pump and rab families revealed very remote diver- gence of compartmentalized isoforms, a group of molecules localizing in cell compartments, possibly going back to an early stage of eukaryotic evolution. Vol. 41, No. 1, 1996 16 Abstracts of 40th Annual Meeting PL-3 RECENT PROGRESS IN MOLECULAR ANALYSIS OF PYRUVATE KINASE DEFICIENCY Hitoshi KANNO (Okinaka Memorial Institute for Medical Research, Tokyo) Pyruvate kinase (PK) deficiency is the most common erythroenzymopathy associated with hereditary hemolytic anemia in Japan. Among 36 PK deficient families which we have analyzed, 16 cases were found to be homozygous, and they included 8 missense, one splicing and one frame-shift mutations. The frame-shift mutant were found to be a null variant of the L-PK gene, suggesting that the null expression of the L/R-PK gene did not cause lethal effects on the PK-deficient subjects and that the affected red cells can survive if reactivation or persistence of the M-PK gene expression is achieved. The biochemical characteristics of the variant enzyme such as the Michaelis constant for phosphoenolpyruvate or the altosteric activation by fructose-l, 6-diphosphate correlate to the expected effects of the missense mutation on the PK subunit. Recent studies showed that 5 unrelated families have the 1261A (Q421K) mutation, suggesting that the 1261A was the most prevalent homozygous mutation in the Japanese PK variants. In compound heterozygotes, 1468T was identified in 11 unrelated families, thus it was the most prevalent mutation among the Japanese PK variants. Using both the 12th exonie and 5th intronic polymorphism which we have found, the DNA haplotype analysis were performed to categorize the five 1261A variants, and revealed these variants were classified into three DNA haplotypes. Recently we found a novel mice model of the PK deficiency, and identified the molecular abnormality. The strain is quite useful for understanding pathophysiology of PK-deficient hemolytic anemia as well as to explore new therapeutic methods for the disease in humans. PL-4 Molecular Basis of Mucopolysaccharidoses The mucopolysaccharidoses (MPS) are group of lysosomal storage disorders caused by deficiency of enzymes catalyzing the stepwise degradation of glycosaminoglycans (mucopolysaccharides). There are 10 known enzyme deficiencies that give rise to six distinct MPS. Depending on the enzyme deficiency, the catabolism of dermatan sulfate, heparan sulfate, chondroitin sulfate or keratan sulfate may be blocked, singly or in combination. Lysosomal accumulation of glycosaminoglycan molecules eventually results in cell, "~issue and organ dysfunction. The MPS share ma~y clinical features, though in variable degrees. These include a chronic and progressive course, mullisystem involvement, organomegaly, dystosis multiplex, mental retardation, and abnormal facies. Hearing, vision, cardiovascular function, and joint mobility may be affected. Recent advanced molecular technology has made it possible to analize most of MPS diseases. First of all, isolation of cDNA and gene in MPS VII has been performed. /3-glucuronidase is a lysosomal enzyme responsible for hydrolysis of glycosaminoglycans, cleaving /3-glucuronosyl residue at the nonreducing end of oligosaccharides. Mutations destroying the function of this enzyme lead to autosomal recessive mucopolysaccharidosis VII. The disease is very heterogeneous and its clinical heterogeneity is due to a large number of mutations within the gene encoding /3-glucuronidase. We represent the mutations and their characterization and show the current status of molecular analysis of this disorder. The identification of mutations has explained a broadening of the spectrum of clinical phenotypes that can be classified and used for accurate and early detection of affected or carrier individuals. 3pn J Human Genet Abstracts of 40th Annual Meeting 17 Mucopolysaccharidosis IVA ( MPS IVA ) is an autosomal recessive disorder caused by a deficiency in N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Studies on the molecular basis of MPS IVA have been facilitated following cloning of the full- length cDNA and genomic DNA. We detected various mutations from over 150 patients using Southern blot and SSCP system and compared mutations of Caucasian origin with those of Japanese origin. The results showed the presence of 32 various mutations (4 small deletions, 2 nonsense and 25 missense mutations for Caucasian patients and 15 (1 deletion, 2 large alteration and 14 missense mutations) for Japanese. Moreover, two common mutations existed; one is double gene deletion characteristic for Japanese (6 alleles; 15%) and the other is a point mutation (Il13F A~T transition) characteristic for Caucasian (9 alleles; 22.5%). Useful 16 polymorphisms were also identified through the entire gene. The clear genotype/phenotype relationship among 1342delCA, IVSI(-2), PI51S, Q148X, R386C, I113F, Q473X, W220G and P77R, for a severe type, G96V N204K and V138A for a milder type was observed. Only R386C and P151L mutations were seen in both of populations. Further the precise DNA analysis for double gene deletion has been performed by defining the breakoints and the results showed that one deletion was caused by homologous recombination due to Alu repetitive sequences and the other was due to nonhomologous recombination of short direct repeat. Haplotype analysis for six alleles with doube deletion were similar except VNTR element, indicating the common ancestral origin of this mutation . Thus the mutaions in GALNS gene are very heterogeneous and the racial difference is characteristic. PL-5 ROLES OF DNA MARKERS IN MEDICINE Yusuke NAKAMURA (Lab. of Mol. Med., Inst. of Med. Sci., Univ. of Tokyo, Tokyo) DNA markers, particularly, polymorphic DNA markers, have significantly contributed to researches in the medical field. I isolated a large number of highly polymorphic markers, called VNTR (variable number of tandem repeat) markers. VNTR are useful for linkage studies for genetic diseases, individual identification including paternity and maternity test in forensic medicine, and loss of heterozygosity (LOH) in cancer tissues in cancer genetics. Particularly, as frequent LOHs in certain chromosomal regions indicate a presence of tumor suppressor genes, VNTR have contributed significantly for detection of candidate loci for tumor suppressor genes. I, combining LOH in colorectal cancer and linkage analysis of families carrying familial adenomatous polyposis (FAP), isolated the APC gene from chromosome 5q21-22 that is responsible for FAP as well as plays a significant role for development of sporadic colorectal adenomas. Vol. 41, No. 1, 1996 18 Abstracts of 40th Annual Meeting Morning Lectures ML-1 PRENATAL AND PREIMPLANTATION DIAGNOSIS. Kaoru SUZUMORI ~ Setsuo OKADA~ Tadashi IIDA~ Manam i KAWAMURA (Dept.