Mutations in the cardiac troponin I gene associated with hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), the most common cause of sudden death in the young, is an autosomal dominant disease characterized by ventricular hypertrophy accompanied by myofibrillar disarrays. Linkage studies and candidate-gene approaches have demonstrated that about half of the patients have mutations in one of six disease genes: cardiac beta-myosin heavy chain (c beta MHC), cardiac troponin T (cTnT), alpha-tropomyosin (alpha TM), cardiac myosin binding protein C (cMBPC), ventricular myosin essential light chain (vMLC1) and ventricular myosin regulatory light chain (vMLC2) genes. Other disease genes remain unknown. Because all the known disease genes encode major contractile elements in cardiac muscle, we have systematically characterized the cardiac sarcomere genes, including cardiac troponin I (cTnI), cardiac actin (cACT) and cardiac troponin C (cTnC) in 184 unrelated patients with HCM and found mutations in the cTnI gene in several patients. Family studies showed that an Arg145Gly mutation was linked to HCM and a Lys206Gln mutation had occurred de novo, thus strongly suggesting that cTnI is the seventh HCM gene.

Mapping of the HLA-linked genes controlling the susceptibility to Takayasu's arteritis.

To further define the HLA-linked genes controlling the susceptibility to Takayasu's arteritis, polymorphisms in five microsatellites around the HLA-B and MICA genes, C1-2-A, MIB, C1-4-1, C1-2-5, and C1-3-1, were investigated in 91 Japanese patients with Takayasu's arteritis and 248 healthy Japanese controls. It was found that allele 238 of C1-2-A [60.4% in patients vs. 29.8% in controls, odds ratio (OR)=3.59, P(c)<0.000004], allele 332 of MIB (22.0% vs. 6. 1%, OR=4.32, P(c)<0.0003), allele 208 of C1-2-5 (47.3% vs. 24.6%, OR=2.75, P(c)=0.001), and allele 291 of C1-3-1 (62.6% vs. 44.8%, OR=2.07, P(c)<0.02) were significantly associated with the disease. Combined analyses of polymorphisms in the HLA-B and MICA genes with those in the microsatellites suggest that there are two different disease-susceptible loci for Takayasu's arteritis; one is mapped near the C1-2-A locus and the other is more closely linked to the HLA-B gene than to the MICA gene, because there are at least two different disease-associated HLA-B haplotypes, HLA-B*52 and -B*39.2 haplotypes, in which the disease-associated C1-2-A allele is shared in common.

MICA gene polymorphism in Takayasu's arteritis and Buerger's disease.

To further clarify the HLA-linked genes susceptible to arterio-vasculitis of unknown etiology, Takayasu's arteritis and Buerger's disease, polymorphism in the MICA gene, a newly identified gene near the HLA-B gene and expressed in epithelial cell lineage, was investigated. Polymerase chain reaction (PCR)-DNA conformation polymorphism (DCP) analysis and subsequent sequencing of the MICA gene have revealed that there are 5 MICA alleles which are different in the number of a GCT repeat in exon 5: MICA alleles MICA-1.1, -1.2, -1.3 and -1.4 have 9, 6, 5 and 4 GCT repeats, respectively, and MICA-1.5 has 5 GCT repeats with a 1 bp frameshift insertion in the repeat. MICA genotyping data in 81 Japanese patients with Takayasu's arteritis, 38 Japanese patients with Buerger's disease, and 160 healthy Japanese controls showed that MICA-1.2 and -1.4 were significantly associated with Takayasu's arteritis and Buerger's disease, respectively. Because MICA-1.2 and -1.4 were in strong linkage disequilibria with HLA-B52 and -B54 in the Japanese populations, respectively, we have compared the odds ratio (OR) of the risk to the diseases for individuals having both or each of the disease-associated MICA and HLA-B alleles. It was found that MICA-1.2 gave a significantly high OR of risk to Takayasu's arteritis in the absence of HLA-B52, suggesting that the HLA-linked gene susceptible to Takayasu's arteritis is mapped near the MICA gene. In contrast, MICA-1.4 gave a significantly high OR of risk to Buerger's disease only in the presence of HLA-B54, suggesting that the HLA-linked gene susceptible to Buerger's disease is linked to the HLA-B54-MICA-1.4 haplotype, and may be differently mapped from that to Takayasu's arteritis.

[Prevalence of pertussis in Fukuoka: incidence and MICs of antibiotics for Bordetella pertussis isolate].

For bacteriological examinations of whooping cough patients, nasopharyngeal specimens were directly inoculated on the cyclodextrin solid medium (CSM) supplemented with 5 micrograms of cephalexin (CEX) per ml. The inoculated plates were cultured in an incubator at 35 degrees C for 3 to 7 days. During the period from 1990 to 1993, B. pertussis (43 strains) and B. parapertussis (1 strain) were isolated from 145 whooping cough patients and 34 relatives. B. pertussis were isolated sufficiently in June to December during the year. It was suggested that during this period epidemics of whooping cough occurred. All isolates of B. pertussis had K antigen consisting of 1, 3, and 6. The determination of minimal inhibitory concentrations (MIC) of antibiotics to B. pertussis was carried out by the micro dilution technique modified from the standard methods. The Stainer-Scholte broth, supplemented with heptakis (2,6-O-dimethyl) beta-cyclodextrin, was used for dilution of the drug, and also for cultivation of bacteria. For determining susceptibility of bacteria to antibiotics, twenty seven isolates of B. pertussis and one of B. parapertussis were precultured on CSM at 35 degrees C for 2 days. The turbidity of broth cultures was adjusted to that of McFarland no. 0.5, and diluted to the concentration of 10(6) CFU/ml. One hundred microliters of these suspensions were added to 25 microliters of each antibiotic solution. After incubation for 3 days at 35 degrees C, the turbidity of the bacteria was read macroscopically for determining the MICs. On the other hand, we compared the agar dilution MICs of 23 antibiotics to the broth microdilution MICs for 27 B. pertussis isolates.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of the human nebulette gene: a polymorphism in an actin-binding motif is associated with nonfamilial idiopathic dilated cardiomyopathy.

Idiopathic dilated cardiomyopathy (IDC) is characterized by a thin-walled heart with systolic dysfunction of unknown etiology. Because abnormalities in genes for cytoskeletal proteins related to Z-disc function have recently been reported to cause IDC, genomic organization of the gene for nebulette, a novel actin-binding Z-disc protein, was determined and its sequence variations were searched for in Japanese patients with IDC and healthy controls. The nebulette gene consists of 28 exons, and four sequence variations leading to amino acid replacement (Gln187His, Met351Val, Asn654Lys, and Thr728Ala) were identified in the patients. These variations were also found in the healthy controls and hence they were polymorphisms and not disease-specific mutations. Frequencies of Gln187His, Met351Val, and Thr728Ala variants were similar in the patients and controls. However, the frequency of homozygotes for Lys at codon 654, a variant at a relatively conserved residue in an actinbinding motif, was significantly increased in nonfamilial IDC patients (n=106) as compared with healthy control subjects (n=331) (7.54% vs 1.21%, OR=6.25, P=0.002, 95% CI=1.92-20.29), while this association was not found in familial IDC patients (n=24). These observations suggest that the nebulette polymorphism in the actin-binding motif was a novel genetic marker of susceptibility to nonfamilial IDC.