摘要:

The regulation of the human apolipoprotein (apo) B gene that plays a crucial role in lipid metabolism is apparently very complex, with multiple cis‐ and trans‐acting regulatory factors. One of these factors is an enhancer region in the second intron. In this region a point mutation at position + 722 has been found that is detectable by the restriction enzyme StyI. The report of Levy‐Wilson et al. (1991) could suggest that the mutant allele (abolished StyI site) is associated with hypocholesterolemia. To investigate further the possible effect of this mutation on plasma cholesterol levels, we have compared the frequency of the mutant allele between 206 hypercholesterolemic Norwegian or Czech subjects on one hand, and 165 hypocholesterolemic Norwegian or Czech subjects on the other hand. No significant difference in frequency was found between the hypercholesterolemic and the hypocholesterolemic groups. This finding indicates either that the mutation at position + 722 does not affect the enhancer activity or that thisin vitroenhancer activity is of little or no clinical significance. One of the Norwegian hypercholesterolemic subjects who was of Czech descent possessed the apoB 3500 mutation that leads to defective binding of low density lipoprotein (LDL) to the LDL receptors. Haplotype analysis of the apoB gene in her family showed that the mutation‐bearing allele was identical to that reported in other countries, indicating a common gene

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03244.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

We have screened exon 11 of the low density lipoprotein receptor (LDLR) gene from familial hypercholesterolemia (FH) heterozygotes for point mutations by using analysis of single strand conformation polymorphisms (SSCP). A variant pattern was observed in three out of 39 subjects. By DNA sequencing, this variant pattern was found to be due to a C→T transition at nucleotide 1617 that affects the third base of codon 518. A PCR method was developed to screen FH heterozygotes and normal subjects for this mutation. The gene frequencies in FH heterozygotes and normal subjects were 4% and 4.5%, respectively. Thus, the mutation cannot be in linkage disequilibrium with a mutation that causes FH. Rather, the mutation may be a useful genetic marker at the LDLR locus. Haplotype analysis at the LDLR locus in two FH families where the proband possessed the mutation revealed that the mutation was on two different haplotypes. This finding is consistent with the mutation occurring at a mutational hot spo

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03245.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Deletion of 15q12 has been reported in patients with Angelman syndrome (AS). We report chromosome studies showing del(15q12) in three new cases, diagnosed as having AS. We were also able to determine, through heteromorphism studies, that the origin of the deleted chromosome in all three probands is maternal. This is a consistent finding in previously reported cases of AS.

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03246.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Myotonic dystrophy (MD) is an autosomal dominant disorder that has a high prevalence in Saguenay‐Lac‐St‐Jean. A case‐control study, based on a population register, of 373 MD patients who married in this region between 1855 and 1971 was conducted to determine whether their fertility was affected by the disorder. Six demographic parameters, that is the number of children, the age at marriage, the ages at the time of birth of the first and the last child, the interval between the marriage and the birth of the first child, and the interval between consecutive births, were analyzed. The mean number of children born to MD and control individuals was not different (P>0.05). However, MD males had more children than MD females although they have started delaying their marriage since 1921. Fertility fell significantly in both the MD and control groups during the period of observation. This change reflects the decline in fertility of French Canadians in general during this period, but mainly aft

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03247.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The clinical and radiographic features of a brother and sister with the Dyggve‐Melchior‐Clausen syndrome are presented. These features differentiate this syndrome from other bone dysplasias causing short trunk dwarfism. In addition to the vertebral, pelvic and proximal limb defects typical of this syndrome, both these patients have more severe distal limb involvement than has been described previously. Their parents are first cousins and have four other unaffected children, which supports an auto‐somal recessive mode of inheritance for this syndrome. The ancestors of this kindred emigrated to South Africa from India in the 19th ce

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03248.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A 10‐year‐old boy with ade novodel(16)(q12.1q13) and many features of the deletion 16q phenotype is described. The deletion occurred in a paternal chromosome as demonstrated by DNA studies with polymorphic (AC)n microsatellite repeat markers. Comparison with published cases suggests that deletion of either of two regions (q13 and q22.1) on the long arm of chromosome 16 is associated with an apparently identical phenotype. No parental imprinting of this region was demonstra

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03249.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A study for screening of β‐thalassaemia mutations by the Amplification Refractory Mutation System (ARMS) and haplotyping by Polymerase Chain Reaction (PCR) was undertaken because there was a paucity of data in Tamil Nadu in Southern India and to initiate a comprehensive prenatal diagnosis programme. A total of 294 alleles were analysed to study the nature of the mutations, of which 146 were β‐thalassaemia alleles. Only four types of β‐thalassaemia mutations were recorded. Of these, 128 alleles were of the variant IVS‐1 nt 5 (G→C). Thirteen had the mutation codon 41/42 (del TCTT), four had the mutation codon 8/9 (insert G) and one had the 619 bp deletion at the 3′ end of the gene. The most common mutation, IVS–1 nt 5 (G→C), was strongly associated with a single haplotype although the association was not absolute. The population of Tamil Nadu in Southern India seems to be ideal for initiating a prenatal diagnosis programme based on direct detection of mutation by ARMS coupled with RFL

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03250.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Chimerism in humans is usually found only because of discrepancies in unique blood group typing or sex chromosome complements. We describe a case found because of an inherited chromosomal translocation. A female carrier of the balanced reciprocal translocation t(14;20)(q31; q13.3) had a twin pregnancy. After birth the B‐twin, a girl, was found to have the balanced translocation. The A‐twin, a severely malformed and stillborn boy, had two different karyotypes; a normal 46,XY and an unbalanced translocation derivative 46,XY, – 14, + der(14)t(14;20)(q31;q13.3). He was a dispermic chimera, formed by two fertilized oo

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03251.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

The significance of variation within the genes coding for three glucose transporter proteins in the aetiology of non‐insulin dependent diabetes mellitus was assessed by analysing restriction fragment length polymorphisms in an English Caucasian population. Two polymorphisms at the HepG2/erythrocyte glucose transporter (GLUT1) locus, four at the liver/ pancreatic glucose transporter (GLUT2) locus and one at the muscle/ adipocyte glucose transporter (GLUT4) were analysed in a sample of diabetic and non‐diabetic subjects. No significant differences in the allelic, genotypic or haplotypic frequencies of the polymorphisms at these three loci were observed between the diabetic or non‐diabetic populations. No significant linkage disequilibrium was observed between the two GLUT1 polymorphic sites, whereas the four polymorphic sites at the GLUT2 locus, one of which appears to be due to a 100–200 base pair DNA insertion/deletion, were found to be in significant linkage disequilibrium. In order to study the possible role of glucose transporter gene variants contributing to the development of obesity, the body mass indexes were compared in the different genotypic groups of diabetic and non‐diabetic subjects. No differences in body mass index between genotype groups were found at the p<0.005 level of sig

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03252.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

A number of selective staining techniques have been utilized to decipher the variability of pericentromeric heterochromatin. One such technique is called DA/DAPI and it is believed to be stain specific. However, we demonstrate otherwise and suggest that pericentromeric regions ofallhuman chromosomes stain positive by DA/DAPI‐technique. It must be emphasized that the incidence of DA/DAPI positive stained chromosomes, other than 1, 9, 15, 16 and Y, is a rare occurrence and only a small portion of the pericentromeric region is DA/DAPI positive, as reported here using 50 normal individual

ISSN:0009-9163    

DOI:10.1111/j.1399-0004.1992.tb03253.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY