Haplotype analysis of the low density lipoprotein receptor (LDLR) gene was performed in Norwegian subjects heterozygous for familial hypercholesterolemia (FH). Southern blot analysis of genomic DNA, using an exon 18 specific probe and the restriction enzyme NcoI, showed that two out of 57 unrelated FH subjects had an abnormal 3.6 kb band. Further analyses revealed that this abnormal band was due to a 9.6 kb deletion that included exons 16 and 17. The 5' deletion breakpoint was after 245 bp of intron 15, and the 3' deletion breakpoint was in exon 18 after nucleotide 3390 of cDNA. Thus, both the membrane-spanning and cytoplasmatic domains of the receptor had been deleted. A polymerase chain reaction (PCR) method was developed to identify this deletion among other Norwegian FH subjects. As a result of this screening one additional subject was found out of 124 subjects screened. Thus, three out of 181 (1.7%) unrelated Norwegian FH subject possessed this deletion. The deletion was found on the same haplotype in the three unrelated subjects, suggesting a common mutagenic event. The deletion is identical to a deletion (FH-Helsinki) that is very common among Finnish FH subjects. However, it is not yet known whether the mutations evolved separately in the two countries.
We determined whether the polymorphism of the gene encoding adiponectin contributes to susceptibility to preeclampsia. The study involved 133 Finnish women with preeclampsia and 245 healthy control subjects. All women were genotyped for two single nucleotide polymorphisms (SNPs), SNP45 in exon 2 and SNP276 in intron 2, in the adiponectin gene. Chi2 analysis was used to assess genotype and allele frequency differences between the preeclamptic and control groups. In addition, the pair of loci haplotype analysis, using the expectation-maximization (EM) algorithm, was used to examine the estimated haplotype frequencies of the two SNPs, among the two groups. The TT genotype versus the pooled G genotypes in SNP276 was associated with protection against preeclampsia (p = 0.012) at an odds ratio of 0.27 (95% confidence interval [CI]: 0.09-0.80). Also the genotype and allele frequency distributions of SNP276 differed significantly between the preeclampsia group and the control group (p = 0.035 and p = 0.043, respectively). Single-point genotype and allele distributions in SNP45 of the adiponectin gene were not statistically different between the groups. In the haplotype estimation analysis, the pooled G haplotypes versus the TT haplotype were significantly overrepresented in the preeclampsia group (p = 0.042 +/- 0.005). Polymorphisms of the adiponectin gene show a weak, but statistically significant, haplotype association with susceptibility to preeclampsia in Finnish women.
X-linked adrenoleukodystrophy is a peroxisomial disorder caused by mutations in the ABCD1 gene. Adrenomyeloneuropathy is the second most frequent phenotype (25-46%) of this disease and classically presents in adulthood with spastic paraparesis. Female heterozygotes can be symptomatic, but they are frequently misdiagnosed as having multiple sclerosis.
We report a novel missense mutation in the ABCD1 gene in a 47-year-old French-Canadian female with spastic paraparesis and no confirmed family history of X-linked adrenoleukodystrophy. The mutation is located on exon 1 and causes the amino acid substitution of a valine for an alanine in a region of the protein highly conserved between mouse and man.
Adrenomyeloneuropathy must be considered in the differential diagnosis of spastic paraparesis in men or women. This is an initial report of an ABCD1 gene mutation in the French-Canadian population, which should lead to the recognition of other cases in the future.
The pathogenesis of pituitary adenomas remains a subject of interest. Recently, mutations in the aryl hydrocarbon receptor-interacting protein (AIP) were identified as germline events leading to pituitary tumor predisposition in Finnish and Italian families with familial growth hormone-secreting pituitary adenomas and acromegaly. We examined the frequency of AIP mutations in pituitary tumors and blood of Canadian patients with sporadic pituitary somatotroph adenomas and sporadic pituitary adenomas of other types. Genomic DNA was extracted from pituitary tumors and white blood cells obtained from peripheral blood. Three PCR reactions were carried out to amplify the sites of known mutation, and amplified products were sequenced. AIP mutations were not detected as germline events in blood or as somatic alterations in tumors of 66 patients with pituitary adenomas. These included 50 acromegalics and 16 patients with other types of pituitary tumor. No mutations were detected in the blood of 22 controls and 10 patients with other endocrinopathies. Our results indicate that mutations in AIP are not identified in sporadic pituitary adenomas of Canadian patients. This rare mechanism of pituitary tumorigenesis appears to be unique to the initial Finnish and Italian families described.
Chuvash polycythemia results from a homozygous 598C>T mutation in exon 3 of the von Hippel-Lindau (VHL) gene. This disrupts the normoxia pathway for degrading hypoxia inducible factor (HIF)-1alpha and HIF-2alpha causing altered expression of HIF-1 and HIF-2 inducible genes. As hypoxia induces expression of pro-inflammatory cytokines, we hypothesized that there might be an elevation of Th1 cytokines in the setting of Chuvash polycythemia. We analyzed plasma concentrations of Th1 (interleukins-2 and 12, interferon-gamma, granulocyte-monocyte colony-stimulating factor, tumor necrosis factor-alpha) and Th2 cytokines (interleukins-4, 5, 10, and 13) using the Bio-Plex multiplex suspension array system in 34 VHL598C>T homozygotes and 32 VHL wild-type participants from Chuvashia. Concentrations of all the Th1 and Th2 cytokines measured were elevated in the VHL598C>T homozygotes compared with the control wild-type participants, but the ratios of Th1 to Th2 cytokines did not differ by genotype. In parallel, peripheral blood concentrations of CD4 positive T-helper cells and CD4/CD8 ratio were lower in the VHL598C>T homozygotes. In conclusion, the up-regulated hypoxic response in Chuvash polycythemia is associated with increased plasma products of both the Th1 and Th2 pathways, but the balance between the two pathways seems to be preserved.
Cites: Med Sci Sports Exerc. 2005 May;37(5):768-7415870630
Cites: Genes Dev. 2000 Aug 15;14(16):1983-9110950862
Cites: BMC Pulm Med. 2005;5:815978129
Cites: Exp Physiol. 2005 Nov;90(6):791-716157658
Cites: Cancer Res. 2006 Mar 1;66(5):2600-716510578
OBJECTIVES: Mannose-binding lectin (MBL) is active in the innate immune defense against microorganisms. In this study, we determined whether vulvar vestibulitis syndrome, a disorder of unknown etiology, was associated with an altered distribution of MBL alleles. STUDY DESIGN: Buccal swabs were obtained from women with vulvar vestibulitis syndrome in New York (62) and from 2 cities in Sweden (60), as well as control women in New York (48) and Sweden (51). DNA was tested for a single nucleotide polymorphism at codon 54 in exon I by polymerase chain reaction, endonuclease digestion, and gel electrophoresis. Blood samples were also obtained from the New York women and tested by ELISA for plasma MBL concentrations. The relationships between genotype, allele frequencies, blood MBL levels, and diagnosis were analyzed by Fisher exact test and one-way analysis of variance. RESULTS: The variant MBL allele, MBL*B, was detected in 35.5% and 26.7% of vulvar vestibulitis patients from New York and Sweden, respectively. Only 12.5% of New York controls (P=.007) and 9.8% of Swedish controls (P=.01) were MBL*2-positive. All women, with one exception, who were positive for MBL*B were MBL*A/MBL*B heterozygotes. Women who carried MBL*B had almost a 10-fold reduction in median plasma MBL concentrations (278 ng/mL), as opposed to women who were MBL*A homozygotes (1980 ng/mL) (P
The results of DNA analysis of deletion in exons 7 and 8 of SMN gene, and exon 5 of NAIP gene in 24 SMA-families from Ukraine are presented. Deletions of SMN exons 7 and 8, or 7 were found in 46 (97.9%) of 47 SMA-chromosomes. A homozygous deletion of NAIP exon 5 was demonstrated in 4 (19%) of 21 SMA-families. The authors have demonstrated that in 2 SMA patients with homozygous deletion SMN exon 7 only, the remaining SMN exon 8 was a part of a chimeric CBCD41/SMN gene.
Hereditary nonpolyposis colon cancer (HNPCC) has been shown to be caused by mutations in the mismatch repair genes hMSH2, hMLH1, hPMS1, and hPMS2. Recent evidence has demonstrated that mutations in mismatch repair genes disrupt meiosis in mice. A large HNPCC kindred in Newfoundland, Canada, has an hMSH2 mutation-an A-->T transversion at the +3 position of the splice-donor site of exon 5. We have studied sperm from men with this hMSH2 mutation, since it is possible that mismatch repair mutations in humans might also have an effect on meiosis and normal segregation of chromosomes. The frequencies of aneuploid and diploid sperm were determined in 10 men with the hMSH2 mutation, by use of multicolor FISH analysis for chromosomes 13, 21, X, and Y. A minimum of 10,000 sperm per man was studied per chromosome probe. Control individuals consisted of men in the same kindred with HNPCC who did not carry the mutation and of other normal men from Newfoundland. A total of 321,663 sperm were analyzed: 200,905 sperm were from men carrying the hMSH2 mutation and 120,758 sperm were from control men. There was a significantly increased frequency of disomy 13, disomy 21, XX, and diploidy in mutation carriers compared with control men. These results suggest that the hMSH2 mutation may affect meiosis in humans.
Cites: Teratology. 1975 Aug;12(1):11-261162621
Cites: Lancet. 1981 Jul 25;2(8239):169-726114243
Cites: Am J Hum Genet. 1991 Aug;49(2):253-601867189
Cites: Science. 1994 Mar 18;263(5153):1625-98128251
Cites: Genetics. 1994 Mar;136(3):953-648005447
Cites: Cancer Res. 1994 Sep 1;54(17):4590-48062247
Cites: Hum Reprod. 1998 Sep;13(9):2489-949806273
Cites: Cell. 1995 Jul 28;82(2):309-197628019
Cites: Cell. 1995 Jul 28;82(2):321-307628020
Cites: Proc Natl Acad Sci U S A. 1995 Nov 7;92(23):10450-67479818
Cites: Nat Genet. 1996 Jul;13(3):336-428673133
Cites: Genes Dev. 1997 Jun 15;11(12):1573-829203583
Hepatolenticular degeneration (HLD) is a severe autosomal-recessive disorder of the copper metabolism. It is characterized by excessive accumulation of copper in the brain and in viscera and is conditioned by the damage in the gene of copper ATP-ase (ATP7B). The paper presents the results of screening of ATP7B gene mutation in 42 patients with HLD from Russian population. The regions of ATP7B gene that are the most frequently exposed to the mutation have been studied (the exzones 14, 15, 16, 18). It is demonstrated that A-->C mutation in the 14-th exzone that led to the change of histidine1069 amino acid for glutamine, was found in more than 60% of patients--Slavs from the European Russia. This mutation was observed in both homo- and heterozygous states. The deletion of (CCC-->CC) nucleotide in the 15-th exzone of the gene was observed in 2 cases. The detailed analysis of the clinical-genetic correlations was performed in patients with the determined damages of ATP7B gene. In Russia the experience of the direct DNA-diagnosis of HLD is described for the first time. It is significant for early evaluation of the patients in preclinical state and for prescription of the preventive copper-eliminating therapy.