Hypokalemic periodic paralysis (HOKPP) is an autosomal dominant neuromuscular disorder characterized by flaccid paralysis accompanied by lowered serum potassium levels. We have tested polymorphic markers linked to the adult skeletal muscle sodium channel (SCN4A) locus at 17q23-q25, the T-cell receptor beta (TCRB) locus at 7q35, and the H-Ras cellular proton-cogene locus (HRAS) at 11p15.5 for linkage with the affected phenotype in a single multigenerational pedigree. No evidence for genetic linkage to HOKPP was found at any of the candidate loci.

Chromosome Mapping↗

PubMed1992

Dinucleotide repeat polymorphism at the human gene for cardiac beta-myosin heavy chain (MYH6).

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Base Sequence↗

PubMed1992

Mapping of the formin gene and exclusion as a candidate gene for the autosomal recessive form of limb-girdle muscular dystrophy.

Limb-Girdle Muscular Dystrophy (LGMD) is a myopathy with clinical and transmission heterogeneity. The recessive form, LGMD2, has been recently mapped by linkage analysis to 15q. As an attempt to identify the gene involved in this pathology, we tested as candidate gene the LD locus, called LD for limb deformity. This gene has recently been identified and mapped to chromosome 15q13-q14. It is homologous to the murine formin gene which is localized to mouse chromosome 2. Mutations in this murine gene have been shown to cause limb deformity and kidney defect. YAC clones containing the LD gene were isolated and utilised to confirm the cytogenetic localisation. Internal DNA polymorphisms of the LD locus were analyzed in LGMD2 and CEPH families. The LD gene was mapped between the alpha cardiac actin gene and the D15S24 locus. Crossovers between the LGMD2 and the LD loci excluded the LD gene as a candidate for LGMD2.

Base Sequence↗

PubMed1992

A minisatellite from bovine which produces highly polymorphic DNA fingerprint patterns in mammals and chickens.

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Animals↗

PubMed1992

Confirmation of genetic heterogeneity in limb-girdle muscular dystrophy: linkage of an autosomal dominant form to chromosome 5q.

Limb-girdle muscular dystrophy (LGMD) is a clinically and genetically heterogenous group of disorders, with both recessive and dominant forms reported. Recently, a series of recessive LGMD families were linked to chromosome 15q. We report herein the results of our linkage studies in a previously reported large autosomal dominant family. The LGMD gene in this family was localized to chromosome 5q22.3-31.3 by using a series of CA(n) microsatellite repeat markers. Linkage to 15q was excluded. These findings confirm genetic heterogeneity in this clinically diverse syndrome.

Cell Line, Transformed↗

PubMed1991

Chromosomal mapping of two genetic loci associated with blood-pressure regulation in hereditary hypertensive rats.

The spontaneously hypertensive rat and the stroke-prone spontaneously hypertensive rat are useful models for human hypertension. In these strains hypertension is a polygenic trait, in which both autosomal and sex-linked genes can influence blood pressure. Linkage studies in crosses between the stroke-prone spontaneously hypertensive rat and the normotensive control strain Wistar-Kyoto have led to the localization of two genes, BP/SP-1 and BP/SP-2, that contribute significantly to blood pressure variation in the F2 population. BP/SP-1 and BP/SP-2 were assigned to rat chromosomes 10 and X, respectively. Comparison of the human and rat genetic maps indicates that BP/SP-1 could reside on human chromosome 17q in a region that also contains the angiotensin I-converting enzyme gene (ACE). This encodes a key enzyme of the renin-angiotensin system, and is therefore a candidate gene in primary hypertension. A rat microsatellite marker of ACE was mapped to rat chromosome 10 within the region containing BP/SP-1.

Animals↗

PubMed1991

Paramyotonia congenita and hyperkalemic periodic paralysis are linked to the adult muscle sodium channel gene.

The hyperkalemic periodic paralyses are a clinically heterogeneous group of autosomal dominant syndromes characterized by episodic paralysis associated with an elevated serum potassium level. Affected individuals in the same family tend to have homogeneous symptom complexes, although phenotypic variation is present among different families. For example, myotonia is absent in some pedigrees, present in others, and, in a third variant, paramyotonia congenita, myotonia coexists with cold-induced paralysis. Electrophysiological studies have demonstrated variant-specific abnormalities in skeletal muscle membrane sodium conductance. We tested the hypothesis that hyperkalemic periodic paralysis (without myotonia) and paramyotonia congenita are tightly linked to the tetrodotoxin-sensitive adult skeletal muscle sodium channel gene on chromosome 17q23-25 in two large pedigrees. The DNA polymorphisms detected in the growth hormone skeletal muscle sodium channel complex (GH1-SCN4A) and by flanking polymorphic markers (D17S74 and D17S40) demonstrated no recombinants between the disease phenotypes and this complex. Phenotypic variation in the hereditary hyperkalemic periodic paralyses may result from allelic heterogeneity at the tetrodotoxin-sensitive adult skeletal muscle sodium channel locus.

Adult↗

PubMed1990

Toward a unified approach to genetic mapping of eukaryotes based on sequence tagged microsatellite sites.

The genomes of all eukaryotes appear to contain a special class of loci, termed microsatellites, which can serve, if sequenced and taken as the substrate for the polymerase chain reaction, as highly informative, locus-specific markers. By analogy to the "sequence tagged sites" recently proposed by Olsen et al. for standardizing the human physical gene map, these microsatellite markers are termed "sequence tagged microsatellite sites" (STMS). Genetic maps based on STMS will share with the Olsen physical maps the advantage that mapping vocabularies will be standardized to the DNA sequence base and that access to any particular locus will not require shipping or storing cloned probes. The species map will consist simply of a listing of nucleotide sequences. Reference populations for developing STMS maps can be chosen on the basis of biological or economic interest. It will not be necessary to maximize for genetic divergence.

Animals↗

PubMed1978

Transcription and processing of intervening sequences in yeast tRNA genes.

Genes for yeast tRNATyr and tRNAPhe have been sequenced (Goodman, Olson and Hall, 1977; Valenzuela et al., 1978) which contain additional nucleotides (intervening sequences) within the middle of the gene that are not present in the mature tRNA. We have isolated precursors to rRNATyr and tRNAPhe from a yeast temperature-sensitive mutant (at the rna1 locus) which accumulates only certain precursor tRNAs at the nonpermissive temperature. The tRNATyr and tRNAPhe precursors were analyzed by oligonucleotide mapping; they each contain the intervening sequence and fully matured 5' and 3' termini. Furthermore, these precursors were used as substrates to search for an enzymatic activity which can remove the intervening sequences and religate the ends. We have shown that wild-type yeast contains such an activity, and that this activity specifically removes the intervening sequences to produce mature-sized RNAs.

Base Sequence↗

PubMed1977

Cloning of yeast transfer RNA genes in Escherichia coli.

Four thousand Escherichia coli clones containing yeast DNA inserted into the plasmid pBR313 have been isolated. Of these, 175 clones were identified as carrying yeast transfer RNA genes. The initial analysis of the inserted transfer RNA genes via the colony hybridization technique with individual radioactive transfer RNA species is reported. The data indicate that yeast transfer RNA genes are not highly clustered, although some clustering exists. In addition, it was observed that the reiteration number of different transfer RNA genes may vary extensively.

Chromosome Mapping↗