Analysis of human Y-chromosome-specific reiterated DNA in chromosome variants

The G-to-T point mutation in codon 34 of the factor XIII gene and the risk of pre-eclampsia

A G-to-T point mutation in exon 2 of the FXIII A-subunit gene results in a leucine rather than valine at amino acid position 34 of the factor XIII molecule. The presence of leucine has been associated with a reduced risk of both arterial and venous thrombosis. We examined the prevalence of this point mutation in 102 cases of pre-eclampsia and 208 matched control subjects, as inherited and acquired risk factors for arterial and venous thrombosis are associated with an increased risk of pre-eclampsia. The GT genotype was observed in 38% of controls and 29.4% of cases and the TT genotype was observed in 6.7% of controls and 5.9% of cases. In subjects heterozygous for the T genotype (GT) the relative risk of pre-eclampsia was 0.7 [95% confidence interval (CI95 ) 0.4-1.1] when compared with the GG genotype. For subjects homozygous for the T allele the relative risk for pre-eclampsia was 0.8 (CI95 0.3-2.1) when compared with the GG genotype. The risk associated with the T allele in the heterozygous and homozygous forms compared with the GG genotype was 0.7 (CI95 0.4-1.1). We conclude that the presence of leucine at this site is not associated with a protection against pre-eclampsia to the magnitude of that reported in other thrombotic disease.

Genetic profiling of colorectal cancer liver metastases by combined comparative genomic hybridization and G-banding analysis

The majority of genetic studies of colorectal carcinogenesis have focused on changes found in primary tumors. Despite the fact that liver metastases are a leading cause of colorectal cancer deaths, the molecular genetic basis of the advanced disease stages remains poorly understood. We performed comparative genomic hybridization (CGH) on 17 liver metastases from colorectal carcinomas and compared the quantitative profile with the qualitative profile previously obtained with chromosome banding. An average of 12.6 aberrations per tumor was found by CGH. Chromosome 18 and chromosome arms 4q, 8p, and 17p were most frequently lost, whereas chromosomes 7 and 20 and chromosome arms 6p, 8q, and 13q were most frequently gained. We compared the chromosome banding and CGH data after converting the karyotypes into net copy number gains and losses. Ten tumors showed agreement between the findings of the two techniques, whereas five tumors did not (in two cases, no mitotic cells were obtained for banding analysis). All five discordant cases had a "simple" abnormal or normal karyotype, but revealed multiple changes by CGH. A likely explanation for this discrepancy is that in vitro growth before G-banding selected against the cancer cells. Interestingly, by comparing the CGH profiles of the "complex" vs. the "simple"/normal karyotype groups, deletion of 8p and gain of 16q were seen more frequently in the former group. The liver metastases had the same aberrations as seen in primary colorectal carcinomas, summarized in a literature survey. However, these aberrations were seen more frequently in liver metastases, which may be attributable to increased genetic instability.

Association of lipoprotein lipase gene Asn291Ser DNA polymorphism with plasma lipid levels and blood pressure levels in healthy population of Serbia

The lipoprotein lipase (LPL) Asn291Ser polymorphism has been determined in 313 healthy subjects from Serbia. LPL variants were detected by mismatch PCR followed by RsaI restriction digestion and 5% polyacrylamide gel electrophoresis. The relationship between LPL Asn291Ser polymorphism and plasma lipid levels, and association between Asn291Ser polymorphism and arterial blood pressure were found. Significant decrease in high-density lipoprotein cholesterol levels (p<0.05) and significantly higher values of systolic blood pressure (SBP) (p<0.01) were found in females carrying the Ser291 allele. Male carriers of Ser291 allele had significantly lower levels of SBP (p<0.01). Findings from our study could be of importance for further research of pathological state regarding lipid metabolism and other risk factors of vascular diseases in Serbian population.

Angiotensin II type 1 receptor gene polymorphism and essential hypertension in Serbian population

Essential hypertension is considered to be a multifactorial trait resulting from the combined influence of environmental and genetic determinants. Due to the controversial results about the role of the ATR1 gene locus in hypertension and understanding that ethnic origin should be carefully considered in studying the association between gene polymorphism and disease etiology, we investigated the role of A1166C polymorphism in Serbian hypertensives. A total of 298 subjects, 100 hypertensive and 198 normotensive, age- and sex-matched controls, were included in this study. All subjects were genotyped for the A1166C polymorphism in ATR1 gene using allele-specific PCR-based technique. There were significant differences in both allele and genotype frequencies between hypertensive and normotensive male subjects (p<0.05). There is significant association between hypertension and CC genotype (CC vs. AC+AA OR=2.56, p=0.04) in the males only. These results suggest that a genetic variant of the ATR1 gene locus influences the risk of essential hypertension in the sex-specific manner in the Serbian population.

Increased frequency of angiotensin-converting enzyme DD genotype in Saudi overweight and obese patients

BACKGROUND

Several studies have been carried out to investigate the insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) in obese and normal weight individuals, often with contradictory results in different populatios. In some studies, the DD genotype occurs at a high frequency in obesity, while in others no association has been demonstrated. Since obesity and overweight are of frequent occurrence in the Saudi population, we initiated this study to investigate the I/D polymorphism of ACE in obese, overweight and normal weight Saudis.

PATIENTS AND METHODS

The study group included 457 Saudi males and females. The height and weight were measured and body mass index (BMI) was calculated. Based on the BMI value, the total study population was classified as normal, overweight and obese. A total of 117 obese (BMI >30 (kg/m(2))), 185 overweight (BMI=25-29.9 (kg/m(2))) and 155 normal weight individuals (BMI< (kg/m (2)) were enrolled. Polymerase chain reaction (PCR) and agarose gel electrophoresis were used to study the ACE polymorphism. For the deletion (D) form, a 190 bp and for the insertion (I) form, 490 bp DNA fragment were obtained on 2% agarose gel electrophoresis.

RESULTS

The frequency of DD genotype was 76.9% in the obese, and 73.5% in the overweight individuals, compared to 19.66% and 24.86% of the ID genotype in the obese and overweight, respectively. Among the normal weight individuals, the frequency was significantly lower for DD and higher for the ID genotype, i.e., 58.7% for DD and 40% for ID. The allele frequencies in the obese were 0.867 and 0.133 for the D and I alleles, respectively. While in the overweight, the frequencies were 0.859 and 0.141 for these alleles, respectively, compared to 0.787 and 0.213 in the normal weight individuals.

CONCLUSIONS

The DD genotype and D allele occur at a high frequency in Saudi overweight and obese individuals, and may have some role in fat accumulation by affecting metabolic pathways of fat, thus leading to the development of overweight and obesity.

Decreased blood activity of glucose-6-phosphate dehydrogenase associates with increased risk for diabetes mellitus

Glucose-6-phosphate dehydrogenase (G6PD) deficiency predisposes affected individuals highly susceptible to oxidative stress, which is one of the risk factors for diabetes. To evaluate the relationship between blood level of G6PD activity and diabetes in Taiwan, blood G6PD activity was analyzed among 237 patients with diabetes and 656 healthy subjects. A significant difference in the distribution of G6PD activities as grouped by an increment of 100 U/10(12) red blood cells (RBCs) was observed between diabetic patients and healthy subjects. The odds ratio for diabetes was 1.46 (95% confidence interval = 1.11-1.92) for every decrement of 100 U/10(12) RBC G6PD activities in these subjects. The data indicate that low G6PD activity is another risk factor for diabetes.

Human factor VII deficiency caused by S339C mutation located adjacent to the specificity pocket of the catalytic domain

This report documents our identification of a novel factor VII (FVII) gene mutation in a Japanese boy with FVII deficiency. The proband's FVII activity was 34% and his FVII antigen level was 40% of normal controls. DNA sequence analysis of the proband's FVII gene identified a C to G point mutation at nucleotide position 10 933 in exon 8, which results in the substitution of Cys (TGC) for Ser339 (TCC). Hinf I digestion results indicate the proband and his mother were heterozygous for the mutation. Both wild-type and mutant FVIIs were transiently expressed in COS-1 cells. FVII levels measured in the culture medium of FVII Ser339Cys mutants were markedly reduced as compared to those of cells with FVII wild-type. The amount of intracellular FVII in FVII Ser339Cys mutants was 80% of that in wild-type. In the wild-type FVII, Ser339 is juxtaposed to Asp338, which is positioned at the bottom of the substrate-binding pocket in the protease domain and located adjacent to FVII Cys340, that forms a disulphide bond with Cys368. We suspect that the creation of a novel unpaired cysteine through this mutation leads to abnormal disulphide bonding during protein folding, thereby reducing the secretion of FVII.

Polymorphisms in the osteoprotegerin gene are associated with osteoporotic fractures

Osteoprotegerin (OPG) is a soluble receptor for RANKL and therefore a competitive inhibitor of osteoclast differentiation and activity. With this key role in the control of resorptive activity, we found that OPG is a candidate gene for genetic control of bone mass. We examined the promoter and the five exons with surrounding intron sequences of the OPG gene for polymorphisms in 50 normal patients and 50 patients with osteoporosis. We found 12 polymorphisms. Two sets of four and five polymorphisms, respectively, were in complete linkage. Subsequently, we examined the effect of the informative polymorphisms A163-G (promoter), T245-G (promoter), T950-C (promoter), G1181-C (exon 1), and A6890-C (intron 4) on the prevalence of osteoporotic fractures, bone mass, and bone turnover in 268 osteoporotic patients and 327 normal controls. In A163-G the variant allele G was more common among fracture patients: 34.0% versus 26.3% in normal controls (p < 0.05) and the odds ratio (OR) for a vertebral fracture, if an individual has the G allele, was 1.44 (1.00-2.08). In T245-G the variant allele G was more common in osteoporotic patients: 12.4% versus 6.5% (p < 0.02) and the OR for vertebral fracture, if an individual has the G-allele, was 2.00 (1.10-3.62). G1181-C is located in the first exon and causes a shift in the third amino acid from lysine to asparagine. The CC genotype was less common among fracture patients: 26.3% versus 36.7% in the normal controls (p < 0.01). T950-C and A6890-C were not distributed differently among patients with osteoporosis and normal controls. None of the polymorphisms affected bone mineral density (BMD) or biochemical markers of bone turnover in the normal controls. In conclusion, we have examined the human OPG gene for polymorphisms and found 12. The rare alleles of the A163-G and T245-G were significantly more common among patients with vertebral fractures.

Novel KCNJ2 mutation in familial periodic paralysis with ventricular dysrhythmia

BACKGROUND

Mutations in the KCNJ2 gene, which codes cardiac and skeletal inward rectifying K+ channels (Kir2.1), produce Andersen's syndrome, which is characterized by periodic paralysis, cardiac arrhythmia, and dysmorphic features.

METHODS AND RESULTS

In 3 Japanese family members with periodic paralysis, ventricular arrhythmias, and marked QT prolongation, polymerase chain reaction/single-strand conformation polymorphism/DNA sequencing identified a novel, heterozygous, missense mutation in KCNJ2, Thr192Ala (T192A), which was located in the putative cytoplasmic chain after the second transmembrane region M2. Using the Xenopus oocyte expression system, we found that the T192A mutant was nonfunctional in the homomeric condition. Coinjection with the wild-type gene reduced the current amplitude, showing a weak dominant-negative effect.

CONCLUSIONS

T192, which is located in the phosphatidylinositol-4,5-bisphosphate binding site and also the region necessary for Kir2.1 multimerization, is a highly conserved amino acid residue among inward-rectifier channels. We suggest that the T192A mutation resulted in the observed electrical phenotype.

Linkage disequilibrium and demographic history of the isolated population of the Faroe Islands

The isolated population of the Faroe Islands has a history of recent expansion after being limited to a small size for centuries. Such an isolated population may be ideal for linkage disequilibrium mapping of disease genes if linkage disequilibrium (LD) extends over large regions. Analyses of 18 markers on 12q24.3, spanning a region of 4.3 Mb (16 cM), revealed extensive LD in the Faroese population. Maximum LD was found between marker pairs separated by more than 3.8 Mb. The same region had a maximum LD of only 1.2 and 1.4 Mb respectively in two outbred Danish and British populations analysed here for comparison. The analyses of gene diversity excess at 15 unlinked microsatellite markers did not reveal any sign of a severe bottleneck to have occurred within approximately 1200 years' history of the Faroese population. The extensive LD in this population may, therefore, have arisen primarily by random genetic drift. The implications for future gene mapping studies are discussed.

Relation of the -514C/T polymorphism in the hepatic lipase gene to serum HDL and LDL cholesterol levels in postmenopausal women under hormone replacement therapy

Hepatic lipase (HL) is a lipolytic enzyme that catalyzes hydrolysis of triglycerides and phospholipids in all major classes of lipoproteins. Recently, a -514C/T polymorphism in the promoter region of the HL gene was found to be associated with variations in hepatic lipase activity and serum high density lipoprotein cholesterol (HDL-C) levels. Postmenopausal hormone replacement therapy (HRT) has known favorable effects on serum lipid and lipoprotein levels. In this study, we examined the relation between the -514C/T polymorphism and serum lipid and lipoprotein levels in postmenopausal women prior to and after 3 months of HRT. Significant associations between the -514 C/T polymorphism and HDL-C, low density lipoprotein cholesterol (LDL-C) and apolipoprotein A-I (apo A-I) levels were observed before and/or after 3 months of HRT. With HRT, serum total cholesterol (TC), LDL-C and apolipoprotein B (apo B) levels were reduced significantly (P=0.0001), and HDL-C and apo A-I levels were increased significantly (P=0.0001). However, the degrees of change in lipid and lipoprotein levels due to HRT did not differ significantly between the HL genotypes.

Mutations in ALMS1 cause obesity, type 2 diabetes and neurosensory degeneration in Alström syndrome

Alström syndrome is a homogeneous autosomal recessive disorder that is characterized by childhood obesity associated with hyperinsulinemia, chronic hyperglycemia and neurosensory deficits. The gene involved in Alström syndrome probably interacts with genetic modifiers, as subsets of affected individuals present with additional features such as dilated cardiomyopathy, hepatic dysfunction, hypothyroidism, male hypogonadism, short stature and mild to moderate developmental delay, and with secondary complications normally associated with type 2 diabetes, such as hyperlipidemia and atherosclerosis. Our detection of an uncharacterized transcript, KIAA0328, led us to identify the gene ALMS1, which contains sequence variations, including four frameshift mutations and two nonsense mutations, that segregate with Alström syndrome in six unrelated families. ALMS1 is ubiquitously expressed at low levels and does not share significant sequence homology with other genes reported so far. The identification of ALMS1 provides an entry point into a new pathway leading toward the understanding of both Alström syndrome and the common diseases that characterize it.

No germline mutations in CDKN2A (p16) in patients with squamous cell cancer of the head and neck and second primary tumours

There is increasing evidence that predisposition to some cancers has a genetic component. There is a high incidence of loss of heterozygosity on chromosome 9, in the region of tumour suppressor gene, CDKN2A (also known as p16), in sporadic squamous cell cancer of the head and neck (SCCHN). To investigate the possibility that CDKN2A may be involved in the inherited susceptibility to SCCHN, the 3 coding exons of CDKN2A were sequenced in 40 patients who had developed a second primary cancer after an index squamous cell cancer of the head and neck. No mutations were found and we conclude that CDKN2A mutations do not play a major role in cancer susceptibility in this group.

ATB(0)/SLC1A5 gene. Fine localisation and exclusion of association with the intestinal phenotype of cystic fibrosis

The Na+-dependent amino acid transporter named ATB(0) was previously found to be located in 19q13.3 by fluorescence in situ hybridisation. Genetic heterogeneity in the 19q13.2-13.4 region, syntenic to the Cystic Fibrosis Modulator Locus 1 (CFM1) in mouse, seemed to be associated to the intestinal phenotypic variation of cystic fibrosis (CF). We performed fine chromosomal mapping of ATB(0) on radiation hybrid (RH) panels G3 and TNG. Based on the most accurate location results from TNG-RH panel, mapping analysis evidenced that ATB(0) is localised between STS SHGC-13875 (D19S995) and STS SHGC-6138 in 19q13.3, that corresponds with the immediately telomeric/distal segment of the strongest linkage region within the human CFM1 (hCFM1) syntenic region. Regarding to the genomic structure and exon organisation, our results show that the ATB(0) gene is organised into eight exons. The knowledge of the genomic structure allowed us to perform an exhaustive mutational analysis of the gene. Evaluation of the possible implication of ATB(0) in the intestinal phenotype of CF was performed on the basis of the functional characteristics of the encoded protein, its apparent relevance to meconium ileus (MI) and position in relation to the hCFM1 syntenic region. We have analysed this gene in samples from CF patients with and without MI. Several sequence variations in the ATB(0) gene were identified, although none of them seemed to be related to the intestinal phenotype of CF. Even though no particular allele or haplotype in ATB(0) appears to be associated to CF-MI disease, new SNPs identified should be useful in segregation and linkage disequilibrium analyses in families affected by other disorders caused by the impairment of neutral amino acid transport.

Effect of a COL1A1 Sp1 binding site polymorphism on arterial pulse wave velocity: an index of compliance

-Reduced arterial compliance precedes changes in blood pressure, which may be mediated through alterations in vessel wall matrix composition. We investigated the effect of the collagen type I-alpha1 gene (COL1A1) +2046G>T polymorphism on arterial compliance in healthy individuals. We recruited 489 subjects (251 men and 238 women; mean age, 22.6+/-1.6 years). COL1A1 genotypes were determined using polymerase chain reaction and digestion by restriction enzyme Bal1. Arterial pulse wave velocities were measured in 3 segments, aortoiliac (PWVA), aortoradial (PWVB), and aorto-dorsalis-pedis (PWVF), as an index of compliance using a noninvasive optical method. Data were available for 455 subjects. The sample was in Hardy-Weinberg equilibrium with genotype distributions and allele frequencies that were not significantly different from those reported previously. The T allele frequency was 0.22 (95% confidence interval, 0.19 to 0.24). Two hundred eighty-three (62.2%) subjects were genotype GG, 148 (35.5%) subjects were genotype GT, and 24 (5.3%) subjects were genotype TT. A comparison of GG homozygotes with GT and TT individuals demonstrated a statistically significant association with arterial compliance: PWVF 4.92+/-0.03 versus 5.06+/-0.05 m/s (ANOVA, P=0.009), PWVB 4.20+/-0.03 versus 4.32+/-0.04 m/s (ANOVA, P=0.036), and PWVA 3.07+/-0.03 versus 3.15+/-0.03 m/s (ANOVA, P=0.045). The effects of genotype were independent of age, gender, smoking, mean arterial pressure, body mass index, family history of hypertension, and activity scores. We report an association between the COL1A1 gene polymorphism and arterial compliance. Alterations in arterial collagen type 1A deposition may play a role in the regulation of arterial compliance.

Adenosine triphosphate-binding cassette superfamily transporter gene expression in severe male infertility

Cystic fibrosis transmembrane regulator (CFTR), multidrug-resistant (MDR)1, and multidrug resistance-associated (MRP) proteins belong to the ATP-binding cassette (ABC) transporter superfamily. A compensatory regulation of MDR1 and CFTR gene expression has been observed in CFTR knockout rodent intestine and in an epithelial cell line of human colon, whereas a high homology and similar anion binding site are shared by MRP and CFTR proteins. To provide better insight into the relationship among the expression behavior in vivo of the three genes in human testis, analysis of MDR1 and MRP gene expression in testicular biopsies was performed and related to the presence of CFTR gene mutations in congenital absence of the vas deferens (CAVD: n = 20) and non-CAVD (n = 30) infertile patients with azoospermia or severe oligozoospermia. A CFTR mutation analysis performed in both groups of patients supported the involvement of CFTR gene mutations in CAVD phenotype (85%) and in defective spermatogenesis (19%). Quantitative reverse transcription-polymerase chain reaction analysis of testicular tissue showed a CFTR-independent MDR1 and MRP gene expression in human testis, suggesting that the mechanisms underlying CFTR gene regulation in testis are different from those in intestine. These findings should contribute to the understanding of patterns of in vivo expression of CFTR, MDR1, and MRP genes in CFTR-related infertility.

The effect of cytokine gene polymorphisms on pediatric heart allograft outcome

BACKGROUND

Cytokines play a major role in the inflammatory and immune responses that mediate allograft outcome. Several studies have shown that the production of cytokines varies among individuals and these variations are determined by genetic polymorphisms, most commonly within the regulatory region of the cytokine gene. The aim of this study was to assess the effect of these allelic variations on acute rejection after pediatric heart transplantation.

METHODS

We performed cytokine genotyping using polymerase chain reaction-sequence specific primers in 93 pediatric heart transplant recipients and 29 heart donors for the following functional polymorphisms: tumor necrosis factor-alpha (TNF-alpha) (-308), interleukin (IL)-10 (-1082, -819, and -592), TGF-beta1 (codon 10 and 25), IL-6 (-174), and interferon-gamma (INF-gamma) (+874). The distribution of polymorphisms in this population did not differ from published controls. The patients were classified as either non-rejecters (0 or 1 episode) or rejecters (> 1 episode) based on the number of biopsy proven rejection episodes in the first year after transplantation.

RESULTS

Forty-two of the 69 TNF-alpha patients (61%) in the low producer group were non-rejecters, while 9 of the 24 (37.5%) with high TNF-alpha were non-rejecters (p = 0.047). In contrast, IL-10 genotype showed the opposite finding. Forty-two of the 66 patients (64%) in the high and intermediate IL-10 group were non-rejecters, while 9 of the 26 (35%) in the low IL-10 group were non-rejecters (p = 0.011). The combination of low TNF-alpha with a high or intermediate IL-10 genotype was associated with the lowest risk of rejection (34/49 or 69% non-rejecters). Neither the distribution of the IL-6, INF-gamma, and TGF-beta1 genotype in recipients nor the donor genotype showed any association with acute rejection.

CONCLUSION

Genetic polymorphisms that have been associated with low TNF-alpha and high IL-10 production are associated with a lower number of acute rejection episodes after pediatric heart transplantation.

Polymorphism of tumor necrosis factor-beta and alcohol dehydrogenase genes and alcoholic brain atrophy in Japanese patients

BACKGROUND

Alcohol abuse can induce brain atrophy, but it only occurs in some alcoholics. Many inflammatory cytokines such as tumor necrosis factor (TNF) are produced rapidly in the brain by experimental or clinical injury.

METHOD

To investigate whether genetic polymorphism of TNF was related to alcoholic brain atrophy, we determined restriction fragment-length polymorphisms of the TNF-beta genes in 72 male alcoholics. Computed tomography was used to determine the severity of brain atrophy.

RESULTS

Digestion with NcoI and MspI after polymerase chain reaction amplification showed that the TNFB1 allele frequency was significantly higher in patients with brain atrophy than in those without brain atrophy (chi2 = 10.20, p = 0.0034). A multivariate analysis that included age, total alcohol intake, ADH2 genotype, and TNF-beta genotype showed that the ADH21/21 genotype and TNFB1/B1 genotype are independently associated with alcoholic brain atrophy. These findings suggest that the TNFB1 allele may be associated with alcoholic brain atrophy.

Familial/bilateral and sporadic testicular germ cell tumors show frequent genetic changes at loci with suggestive linkage evidence

Testicular germ cell tumor (TGCT) is the most common tumor type among adolescent and young adult males. Familial clustering and bilateral disease are suggestive of a genetic predisposition among a subgroup of these patients, but susceptibility genes for testicular cancer have not yet been identified. However, suggestive linkage between disease and genetic markers has been reported at loci on chromosome arms 3q, 5q, 12q, 18q, and Xq. We have analyzed primary familial/bilateral (n=20) and sporadic (n=27) TGCTs, including 28 seminomas and 19 nonseminomas, for allelic imbalance (AI) within the autosomal regions. DNA from all tumors were analyzed by fluorescent polymerase chain reaction of 22 polymorphic loci at 3q27-ter, 5q13-35.1, 12q21-ter, and 18q12--ter. All tumor genotypes were evaluated against their corresponding constitutional genotypes. The percentages of TGCTs with genetic changes at 3q, 5q, 12q, and 18q, were 79%, 36%, 53% and 43%, respectively. The frequencies at 3q and 12q in nonseminomas were significantly higher than in seminomas (P=.003 and P=.004). In order to evaluate changes at hemizygous Xq loci, five loci were analyzed by co-amplification with an autosomal reference marker known to reveal retained heterozygosity in the tumor DNA. Gain of Xq sequences was seen in more than 50% of the tumors. The degree of amplification varied among the loci in each of five tumors, and based on these breakpoints, a common region of overlapping gains was found at Xq28. No significant differences were found between the frequencies of genetic changes in familial/bilateral versus sporadic tumors, an observation speaking in disfavor of the existence of a single susceptibility gene for TGCT in any of the analyzed regions. Our data suggest that gain of genetic material at distal Xq and losses at 5q and 18q contribute to establishment of seminomas, whereas imbalances at 3q as well as gain at distal part of 12q are associated with further progression into nonseminomas.

Recurrent leg ulcers and arterial thrombosis in a 33-year-old homozygous variant of antithrombin

We report here a homozygous variant case of antithrombin (AT) associated with arterial thrombosis and recurrent leg ulcers. The deep vein thrombosis was recognized by the venogram of his pelvic veins. His leg ulcers were scattered around his left ankle and accompanied by lipodermatosclerosis, which was evident in venous insufficiency. The propositus had developed cerebral infarction 12 years prior to his leg ulcers. Coagulation study showed low heparin cofactor activity of his AT with a normal level of immunoreactive AT. Nucleotide sequence analysis of the exon 2 of his AT gene showed Arg47-Cys mutation, leading to the lack of affinity of AT for heparin. The propositus is a homozygote for this abnormality.

Chromosomal aberrations in sporadic pituitary tumors

Pituitary adenomas are common intracranial neoplasms that may be hormone-secreting or nonfunctional. Genetic defects associated with some pituitary tumors have been identified, although our understanding of the underlying molecular mechanisms remains incomplete. We have studied 75 sporadic pituitary tumors, representing the major clinical subtypes, by comparative genomic hybridization (CGH) with the aim of assessing for DNA copy number changes. CGH revealed chromosomal imbalances in 34 adenomas (45.3%), whereby gains were 4.9 times more frequently observed than losses. Most of the genetic alterations detected by CGH affected entire chromosomes (108/131, 82.4%). Gain of genetic material was observed predominantly on chromosomes X (24/75, 32%), 19 (12/75, 16%), 12 (6/75, 6.7%), 7 and 9 (5/75, 6.7%), whereas loss of DNA sequences most frequently affected chromosomes 11 (4/75, 5.3%), 13 and 10 (3/75, 4%). There were no significant differences in the CGH results for the individual clinical subtypes of pituitary tumors. These results reveal a nonrandom pattern of chromosomal alterations in pituitary tumors, in particular gains of entire chromosomes, and this may contribute to the development of such neoplasms.

Mutations of the phenylalanine hydroxylase (PAH) gene in Brazilian patients with phenylketonuria

In the present study, 115 Brazilian families with phenylketonuria (PKU), mainly from the Southeast of the country, were studied using three laboratory methods (DGGE, SSCP, and sequencing). All 13 exons of the PAH gene were analyzed, including the splicing sites and the promoter region. We identified 50 distinct mutations and characterized 91% of the mutant alleles. The five most prevalent mutations of the 50 mutations identified (50% of the PKU alleles) were IVS10nt-11G-->A (17.4%), followed by R261Q (12.2%), V388M (9.1%), R252W (6.5%), and R270K (4.8%). The other mutations were rare. The mutation spectrum included 10 novel mutations (IVS5nt-54A-->G, IVS6nt17G-->T, E205A, F240S, K274E, I318T, L321L, C357G, IVS11nt17G-->A, and S411X). To characterize the origin and distribution of the PAH alleles we determined the association between the detected mutations and the PCR/RFLP haplotypes and VNTR alleles located on the PAH gene. For those patients whose mutant alleles were detected, we calculated the correlation with pretreatment phenylalanine levels, thus establishing a genotype/phenotype correlation. The present results confirm the marked heterogeneity observed at the PAH locus and contribute to the understanding of the distribution and frequency of PKU mutations in the Brazilian population.

Characterization and subcellular localization of KCNQ1 with a heterozygous mutation in the C terminus

Numerous mutations in KCNQ1, a gene encoding the alpha -subunit of cardiac delayed rectifier potassium channels, have been found in long QT syndrome (LQTS). Among them, several mutations in the C terminus have been shown to cause autosomal recessive or subclinical autosomal dominant LQTS. Here, we report a heterozygous mutation, T587M, which is also in the KCNQ1 C-terminal domain. The same mutation was found in three independent probands that were clearly symptomatic with family history of cardiac sudden death. Functional assay using a heterologous expression system with a mammalian cell line (COS7 cells) revealed that the mutant displayed neither functional channels when expressed alone nor dominant-negative effect when co-expressed with wild-type (WT) KCNQ1. To examine the cellular trafficking of KCNQ1, green fluorescent protein (GFP) was tagged to the cytoplasmic C terminus of WT or mutant KCNQ1. This procedure did not affect the essential properties of expressed WT KCNQ1 channels. On confocal microscopic images, GFP-tagged WT KCNQ1 showed a plasma membrane fluorescence pattern, whereas the GFP-tagged mutant showed a perinuclear fluorescence pattern. Co-expression of the mutant with GFP-tagged WT KCNQ1 did not influence its normal cellular transport. Therefore, the T587M mutant cannot traffic to the plasma membrane and may form no subunit assembly with WT KCNQ1. These findings provide a novel molecular basis for the clinical finding that this C-terminal mutation produced a severe form of RWS-type LQTS.

Maternal repression of the human GRB10 gene in the developing central nervous system; evaluation of the role for GRB10 in Silver-Russell syndrome

The GRB10 gene encodes a growth suppressor and maps to human chromosome 7p11.2-p13. Maternal duplication (matdup) of this region has recently been associated with Silver-Russell syndrome (SRS), which is characterised by pre- and postnatal growth restriction, craniofacial dysmorphism and lateral asymmetry. Maternal uniparental disomy for chromosome 7 (mUPD7) occurs in approximately 7% of SRS patients. Exposure of a recessive allele due to isodisomy has been ruled out in five mUPD7 cases, suggesting genomic imprinting as the basis for disease. Assuming SRS patients with matdup of 7p11.2-p13 and mUPD7 share a common aetiology, this would implicate a maternally expressed gene from this interval, which is involved in growth inhibition. Murine Grb10 was identified as a maternally expressed gene by subtractive hybridisation using normal and androgenetic mouse embryos. Grb10 maps to the homologous region of proximal mouse chromosome 11, for which mUPD incurs reduced birthweight. A role for GRB10 in SRS was evaluated by determining its imprinting status in multiple human foetal tissues using expressed polymorphisms, and by screening the coding region for mutations in 18 classic non-mUPD7 SRS patients. Maternal repression of GRB10 was observed specifically in the developing central nervous system including brain and spinal cord, with biallelic expression in peripheral tissues. This is in contrast to mouse Grb10, and represents the first example of opposite imprinting in human and mouse homologues. While a role for GRB10 in mUPD7 SRS cases can not be ruled out on the basis of imprinting status, no mutations were identified in the patients screened.

A new mutation in the HNF4 binding region of the factor VII promoter in a patient with severe factor VII deficiency

Investigation of the molecular basis of a severe factor VII (fVII) deficiency revealed compound heterozygosity in the fVII gene. On the paternal allele the patient had 3 structural gene abnormalities frequently associated with fVII deficiency. A new mutation, a C to T transition at position −55 relative to the translational start site, was found on the maternal allele. The study demonstrates that this mutation partially impeded binding of the transcriptional activator, hepatic nuclear factor 4, to the fVII promoter while greatly reducing reporter gene expression in hepatic cells.

A new mutation in the HNF4 binding region of the factor VII promoter in a patient with severe factor VII deficiency

Investigation of the molecular basis of a severe factor VII (fVII) deficiency revealed compound heterozygosity in the fVII gene. On the paternal allele the patient had 3 structural gene abnormalities frequently associated with fVII deficiency. A new mutation, a C to T transition at position −55 relative to the translational start site, was found on the maternal allele. The study demonstrates that this mutation partially impeded binding of the transcriptional activator, hepatic nuclear factor 4, to the fVII promoter while greatly reducing reporter gene expression in hepatic cells.

Mutations in the low-density-lipoprotein receptor gene in German patients with familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is an autosomal dominant disorder of lipid metabolism characterized by elevated low-density lipoproteins (LDL), the formation of tendon and skin xanthomata and the development of premature coronary atherosclerosis. It is caused by a defect in the receptor-mediated hepatic uptake of LDL due to mutations in the LDL receptor. In 25 FH families with a total of 160 members and in two individuals without available relatives, all of German origin, we identified LDL receptor mutations by a multiplex-PCR-based single-strand conformation polymorphism method followed by direct sequencing. Of the 24 mutations found, 15 are missense mutations, 2 are nonsense mutations, 4 are small deletions or insertions leading to frameshifts, 2 are an in-frame insertion and deletion, respectively, and one is a splice site mutation. Propositi carrying mutations that are known to completely abolish receptor function (nonsense and frameshift mutations, missense mutation V480M) had significantly higher untreated total and LDL-cholesterol levels compared to those patients carrying missense and in-frame insertion mutations of unknown functional consequence, which may lead to either reduced or completely abolished receptor function (11.30+/-1.64 vs 9.76+/-1.50 mmol/L, and 9.39+/-1.23 vs 7.99+/-1.45 mmol/L, respectively). These results confirm the clinical and molecular heterogeneity of FH and the influence of different functional classes of mutations on lipid values.

Further evidence for genetic heterogeneity within type II autosomal dominant osteopetrosis

Type II autosomal dominant osteopetrosis (ADO II) is characterized by an increased bone mass that contrasts with the high frequency of fractures. Linkage analysis performed in an extensive Danish family recently provided evidence for the mapping of an ADO II gene to an 8.5-cM region in chromosome 1p21 between microsatellite markers D1S486 and D1S2792. We recruited, phenotyped, and haplotyped 4F catheter ADO II families including 18 affected subjects and 29 unaffected subjects in order to narrow the candidate region and to search for genetic heterogeneity. ADO II diagnosis was ascertained by the observation of vertebral end plate thickening in at least 2 patients from successive generations. Linkage studies involved five microsatellite markers (D1S486, D1S206, D1S495, D1S248, and D1S2792) spanning 1p21. Haplotype analyses of two of our families clearly excluded the tested locus. The two remaining families gave poorly informative results. These results, combined with those previously reported in two American families, suggest that chromosomal region 1p21 is most likely a minor locus for ADO II.

Familial form of hirschsprung disease: nucleotide sequence studies reveal point mutations in the RET proto-oncogene in two of six families but not in other candidate genes

Hirschsprung disease (HSCR; McKusick 142623) or aganglionic megacolon is a frequent (1 in 5,000 live births) heritable disorder of the enteric nervous system. By haplotyping with a variety of microsatellite markers, by amplifying all 20 exons of the RET proto-oncogene and by applying a direct DNA sequencing protocol, we have analyzed the DNA from HSCR patients in 6 different families. In one family with a joint occurrence of HSCR and FMTC (follicular medullary thyroid carcinoma), we have identified a mutation in codon 609 in one out of 6 cysteine residues encoded in exon 10 of the RET gene. This C609R point mutation has not previously been reported to cause HSCR. In 2 of the HSCR patients described here from different families, we have found a mutation in exon 2 (R77C) and a silent mutation in exon 3 (Y204Y), respectively, in the extracellular part of the RET proto-oncogene. In introns 2 and 17 of the RET proto-oncogene in 2 families, we have detected single nucleotide exchanges that are probably polymorphisms with unknown, if any, relations to HSCR. The DNA sequences of 5 further genes (GDNF, GDNFRalpha, EDN3, EDNRB, and NTN), that may contribute to the development of HSCR, have not shown mutations in the patients analyzed so far. In 2 of the reported families with several affected children and one grandchild, sequence analyses revealed no mutations in the coding regions of any of the candidate genes analyzed.

Evaluation of the myosin VIIA gene and visual function in patients with Usher syndrome type I

Usher syndrome type I (USH1) is a recessively-inherited disorder consisting of retinitis pigmentosa, profound congenital deafness, and vestibular ataxia. It can be caused by mutations in at least six different loci (USH1A-1F). The gene encoding human myosin VIIA (MYO7A) is the USH1B locus. In this study, 66 unrelated patients with USH1 were evaluated for defects in MYO7A using single-strand conformation polymorphism analysis and direct genomic sequencing. Twenty-nine per cent of cases were found to have likely pathogenic MYO7A mutations. A total of 22 likely pathogenic changes were identified, 18 of which were novel. Cosegregation analysis of mutations in five available families showed that the MYO7A changes segregated with the disease in an autosomal recessive fashion. Average visual function as measured by visual acuity, visual field area, and ERG amplitude was not significantly different between the group of patients with likely pathogenic MYO7A changes and the group in which no likely pathogenic MYO7A changes were detected.

Analysis of telomeric repeats and telomerase activity in human colon carcinoma cells with gene amplification

COLO320DM and COLO320HSR are cell lines derived from a human malignant neuroendocrine colon carcinoma. Both lines have a 30-40-fold amplification of a large DNA domain containing the MYC oncogene. By using fluorescence in situ hybridization techniques with a MYC probe, we could demonstrate that MYC amplicons are contained in a large marker chromosome in COLO320HSR cells, in double minutes (dmin) of COLO320DM cells, and in the interstitial regions of 3-4 additional chromosomes in both cell lines. Amplicons in homogeneous staining regions (HSRs) comprise normal MYC genes, while dmin chromosomes contain PVT/MYC chimeras. Although both cell lines showed similar levels of telomerase activity, the telomere length and telomere distribution in chromosomal termini were considerably lower in COLO320DM than in COLO320HSR cells. This indicates that the average telomere length in cancer cells is regulated no only by the rates of telomerase activity but also by some other non-enzymatic mechanisms.

Atypical movement disorders in the early stages of Huntington's disease: clinical and genetic analysis

Huntington's disease (HD) is notably difficult to diagnose in the early stages. One reason is that the early clinical manifestations of HD vary widely and sometimes have an atypical onset. In this paper we primarily sought information on affected patients who initially presented with movement disorders other than chorea. We also investigated atypical motor presentations in relation to triplet CAG expansions. After reviewing the clinical records of two neurological centres, we identified patients with a final, documented diagnosis of HD and selected for study 205 patients according to their onset of motor manifestations. CAG repeats were analysed. Of the 205 patients studied, 15 had atypical motor symptoms at onset. In this group we identified three types of initial clinical manifestations other than chorea: parkinsonism, ataxia and dystonia. We conclude that HD patients may have different motor manifestations at the initiation of the illness. Patients with atypical movement disorders in the early stages have larger CAG expansions and an earlier age at onset than HD patients with typical onset chorea.

Molecular diagnostics of 15 hemophilia A patients: characterization of eight novel mutations in the factor VIII gene, two of which result in exon skipping

The X-linked bleeding disorder hemophilia A is caused by mutations in the coagulation factor VIII gene. A high frequency of de novo mutations and the large size of this gene complicate the molecular diagnostic of hemophilia A. Characterization of mutations, however, may help identify amino acids or regions with essential functional or structural properties and thereby clarify the mechanism of pathogenesis. In the present study, we describe the identification of 15 mutations in the factor VIII gene, of which eight are novel. Among the patients with severe hemophilia A, two splice mutations (IVS5-3 and IVS19-2), a 4-bp deletion ((TACA) at codon 1215, and a missense mutation G1850V have been characterized. The missense mutations G479R, R531C, V537D, N2129S and I2190N were found for five patients with a moderate course of hemophilia A disease. A silent mutation resulting in activation of a cryptic acceptor splice site within exon 11 and four other missense mutations Y114C, R1689H, R2150H (2x), M2164V have been identified for six patients with mild hemophilia A.

APO B 3' HVR polymorphism in healthy population: relationships to serum lipid levels

We have analyzed allele frequency distribution at the hypervariable locus 3' to the apolipoprotein B gene in a healthy population sample (241 women and 246 men) from the Belgrade area. The bimodal distribution of sixteen different hypervariable region (HVR) alleles and the heterozygosity index (average 0.76) in both samples are similar to ones reported for other Caucasian populations. However, we found the hypervariable element containing 34 repeats-HVE34 allele to be the most common one in both female and male samples, and that there was a lower frequency of the HVE>36 alleles. For further analysis of 3'HVR allele frequency and its possible association with serum lipid levels, all HVR alleles were grouped into five main types (HVE<32, HVE32, HVE34, HVE36, and HVE>36), and the samples were divided into lipid quartiles. We found that (1) apo B gene 3'HVR polymorphism is associated with variation of normal lipid levels in males, (2) HVE32 alleles are associated with decreased serum levels of total cholesterol, LDL cholesterol, and triglycerides, and (3) HVR genotypes containing HVE34 and HVE36 alleles are associated with elevated serum levels of total cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides.

The effect of a gender difference in the apolipoprotein E gene DNA polymorphism on serum lipid levels in a Serbian healthy population

To date, no data have been available on relationship between apolipoprotein E polymorphism and lipid levels in Serbian populations. Blood samples were obtained from 591 healthy normal individuals (193 women and 398 men). A 244 bp sequence of the apolipoprotein E gene including the two polymorphic sites was amplified by polymerase chain reaction. After digestion with Hhal, DNA fragments were visualized by microplate array diagonal gel electrophoresis. In men, levels of both total and low-density lipoprotein cholesterol among the three apolipoprotein E genotype groups differed significantly (p <0.05). The epsilon2 allele was associated with lower concentrations of both total and low-density lipoprotein cholesterol, where the epsilon4 allele had the opposite effects. No significant effects of apolipoprotein E polymorphism on serum lipid levels were observed in women. The presented data could be taken into consideration in any future disease risk evaluation in this population.

Post-mortem forensic identity testing: application of PCR to the identification of fire victim

CONTEXT

DNA analysis has been used with success in the identification of carbonized corpses and victims of large accidents. The analysis requires relatives of crash victims to donate blood for analysis. The relatives are generally willing contribute to the identification by giving a blood sample.

OBJECTIVE

To describe the use of the polymerase chain reaction (PCR) for genetic characterization of one victim extensively burned by fire.

DESIGN

Case report.

CASE REPORT

DNA was extracted from blood of the cardiac chamber, and 15 different loci (D1S80, ApoB, D17S30, D3S1744, D18S849, D12S1090, FGA, D7S820, D1S533, D9S304, HUMCSF1PO, HUMTPOX, HUMTHO1, amelogenin and HLA-DQA1) were analyzed using the PCR technique. Results from all loci typing of the corpse were then compared to that of his alleged biological parents, revealing a genetic compatibility.

Apparent confined placental mosaicism of trisomy 16 and multiple fetal anomalies: case report

Trisomy 16 is frequently found confined to the placenta (confined placental mosaicism (CPM)), with a structurally normal fetus. In some cases of trisomy 16, the fetus has uniparental disomy for chromosome 16 (UPD16) which is associated with intrauterine growth restriction (IUGR) and fetal anomalies. We report a case of apparent confined placental mosaicism for trisomy 16, using standard cytogenetic techniques, but with multiple fetal abnormalities including congenital diaphragmatic hernia in which there was no evidence of UPD in the disomic tissues examined. Subsequent examination of fetal tissues using fluorescent in situ hybridization (FISH) demonstrated low levels of mosaicism for trisomy 16 in all the tissues examined. The use of FISH permits identification of mosaicism which conventional techniques may not identify.

Genetic polymorphisms of interleukin-1beta in association with the development of alcoholic liver disease in Japanese patients

OBJECTIVE

Cytokine interleukin-1beta plays a central role in the inflammation process. Serum levels of IL-1beta are elevated in patients with alcoholic liver disease (ALD), especially in those with cirrhosis and alcoholic hepatitis. Recently, the presence of genetic polymorphisms of this cytokine was confirmed. The aim of this study was to determine whether IL-1beta polymorphisms are associated with the development of ALD.

METHODS

We examined the frequency of two polymorphisms in the IL-1beta gene located in promoter -511 and exon 5 +3953 locus by restriction fragment length polymorphisms in 142 male patients with ALD, 30 heavy drinkers without ALD, and 218 healthy controls.

RESULTS

The carriers of -511 IL-1beta allele 2 were present significantly more often in patients with alcoholic cirrhosis than in those with noncirrhotic ALD (p = 0.026), heavy drinkers without ALD (p = 0.001), and healthy controls (p = 0.032). The frequencies of allele 2 and heterozygotes of +3953 polymorphism were both significantly higher in heavy drinkers without ALD than in patients with ALD (allele, p = 0.030; genotype, p = 0.027) and healthy controls (allele, p = 0.047; genotype, p = 0.043). The haplotype, IL-1beta -511 allele 2/+3953 allele 1 was associated with the development of alcoholic cirrhosis (p < 0.05).

CONCLUSIONS

These results suggest that IL-1beta polymorphisms may be related to the development of ALD in Japanese alcoholics.

Follow-up of chimerism, including T- and B-lymphocytes and granulocytes in children more than one year after allogeneic bone marrow transplantation

In bone-marrow-transplanted children, early detection of graft failure, relapse, and other potentially treatable problems is facilitated by the use of polymerase chain reaction (PCR) assays that monitor whether blood and marrow cells are of recipient or donor origin. Presence of mixed donor-recipient chimerism (MC) within the first year after BMT frequently correlates with clinical problems. To study if MC detected one year or more post-BMT was also often associated with clinical problems, the chimeric status in 33 children surviving 1-11 yr (median: 2 yr) after BMT was investigated. A PCR with a sensitivity of 1-2%, using fluorescent primers analyzing DNA fragment length polymorphisms, was applied. T- and B-cells and granulocytes were immunomagnetically isolated and tested separately for all patients. Of the 33 patients, of whom 21 had received pretreatment including total body irradiation (TBI), 27 (82%) exhibited full donor chimerism. Six children (18%), four of whom had received pretreatment without TBI, had MC. In three of these children, all with aplastic anemia, isolated T-cell MC had not posed apparent clinical problems. In two patients, both with MC including B-cells, immune hemolytic anemia was observed. A sixth patient with AML presented with MC and relapse. In two of the six children MC was detected only by cell subset analysis. In conclusion, analysis of MC in leukocyte subsets is more informative than analysis of whole blood only and may reveal clinically important variations in the origin of different cell populations. The prevalence of MC is lower after the first year post-BMT, and when present is less often associated with clinical problems.

Characterization of a subcloned fragment (pBA0.6) of pCMM86 located on 17q21 and its potential use in generating an individual-specific DNA profile

Sequence analysis was carried out of a human clone pBA0.6 generated after exonuclease III/S1 nuclease digestion and subcloning of pCMM86 (GDB: 168382, D17S74), which was not available in the database. It revealed the presence of a reiterating core motif of 24mer GTGGGTGTGTTGGAGGGGGTGAGG, present 23 times, which was GC-rich and minisatellitic in nature. Genomic blots of HaeIII-digested human DNA, when hybridized with pBA0.6, generated a ladder of bands between 29.0 kb and 2.1 kb. Hybridization analyses of 88 unrelated individuals belonging to four regions of India using this probe revealed polymorphic bands which were individual specific. The probability of identity ranged from 5.07x10(-14) in Punjabis to 2.64x10(-16) in Bengalis and was found to be 3.06x10(-16) in UPites, whereas in the case of South Indians, it was 3.9x10(-15). Three sets of isomorphic bands at 29.0 kb, 2.4 kb, and 2.1 kb were common between the individuals of all the regions and served as internal markers. The 29.0-kb band was observed to be Homo sapiens specific. Construction of dendrograms based on the UPGMA method with Jaccard's coefficient values suggested less genetic similarity/high genetic diversity in all the population groups, indicating that the samples taken were random. Maximum likelihood estimates through the bootstrap sampling method showed that Punjabis, Bengalis, and UPites formed one cluster, whereas South Indians formed a separate cluster, altogether thus showing the proximity of these three population groups compared with that from South India. A preliminary study by Northern hybridization with pBA0.6 resulted in two transcripts of 0.63 kb and 0.29 kb. This finding was corroborated with RT-PCR results where 2 amplicons, matching the expected size of two open reading frames within the minisatellite sequence, were obtained. The role of the two transcripts from the minisatellite sequence is not clear as yet, and it is probable that these messages may not get translated because of the absence of a eukaryotic Kozak sequence around the initiator methionine in the pBA0.6 sequence.

Loss of Dp140 regulatory sequences is associated with cognitive impairment in dystrophinopathies

Mental retardation is a clinical feature present in both Duchenne and Becker muscular dystrophy patients and its pathogenesis is still unknown. Dp140 is a dystrophin isoform with predominant expression during foetal brain development. Its promoter and first exon lie in the large intron between exon 44 and 45, a region that is commonly deleted in dystrophinopathic patients. We performed neuropsychological evaluation and genetic analysis of the Dp140 transcription unit on 12 Duchenne muscular dystrophy and 28 Becker muscular dystrophy patients carrying deletions in this critical region. Comparison of neuropsychological and molecular data showed that there is a statistically significant relationship between the loss of Dp140 transcription unit and mental retardation in Becker muscular dystrophy patients (P = 0.008). Such a correlation is not evident in Duchenne muscular dystrophy patients but only shows a trend towards significance (P = 0.063). It is worth noting that both Duchenne muscular dystrophy and Becker muscular dystrophy patients with normal intelligence do not show deletions in the Dp140 regulatory regions. In the light of these findings, we suggest that impairment of cognitive abilities in Duchenne muscular dystrophy and Becker muscular dystrophy patients might be related to a dysfunction of Dp140 brain isoform.

Osteoporotic fractures are associated with an 86-base pair repeat polymorphism in the interleukin-1--receptor antagonist gene but not with polymorphisms in the interleukin-1beta gene

Interleukin-1beta (IL-1beta) is a potent stimulator of bone resorption, and has been implicated in the pathogenesis of high bone turnover and osteoporosis. IL-1 receptor antagonist (IL-1ra) is a competitive inhibitor of IL-1beta effects and the biological effects of IL-1beta are therefore proportional to the ratio IL-1beta/IL-1ra. The coding regions of IL-1beta were examined for sequence variations by SSCP and sequencing after polymerase chain reaction (PCR) of genomic DNA. Three previously described polymorphisms (C(-511)-T, G(3877)-A and C(3954)-T) in the IL-1beta gene were determined by restriction fragment length polymorphism (RFLP) using Ava I, Aci I, and Taq I after PCR. The 86-base pair repeat polymorphism in IL-1ra was examined by PCR and electrophoresis and the T11100-C polymorphism in the IL-1ra gene was examined by RFLP using MspA1I after PCR. All polymorphisms were related to bone mass, biochemical markers of bone turnover, and presence of fracture in a study including 389 osteoporotic patients with vertebral fractures and normal controls. Two normal women were heterozygous for a shift from cytosine to thymine (C3263-T) in exon 4 of the IL-1beta gene. This substitution did not affect the amino acid sequence. We did not find other sequence variations in the IL-1beta gene apart from the already known polymorphisms. The distribution of C(-511)-T, G(3877)-A, and C(3954)-T genotypes was similar in the osteoporotic and the normal controls. No significant differences could be shown in bone mass or bone turnover. In the IL-1ra gene almost complete linkage was confirmed between the already known polymorphisms: G(1731)-A, G(1821)-A, A(1868)-G, G(1887)-C, T(8006)-C, C(8061)-T, 86 base pair variable number tandem repeat (VNTR), A(9589)-T, and a new polymorphism: T(1934)-C. The A1A1/A3 genotypes of the IL-1ra VNTR polymorphism were significantly more frequent in osteoporotic patients (56.2%) compared with age-matched normal controls (43.3%) (chi2 = 4.09; p = 0.043). The relative risk of osteoporotic fractures was increased to 1.68 (95% CI, 1.01-2.77) in individuals with A1A1/A3 genotypes. Bone mineral density (BMD) of the lumbar spine was reduced in individuals with A1A1/A3 genotypes (p = 0.014, analysis of variance [ANOVA]). The difference in bone mass between A1A1/A3 and A2A1/A2 tended to increase with increasing age. T1100-C genotypes were distributed similarly in osteoporotic patients and normal controls and the polymorphism was without effect on bone mass and biochemical markers of bone turnover. In conclusion, an 86-base pair repeat polymorphism in the IL-lra gene is associated with increased risk of osteoporotic fractures. Other polymorphisms in the IL-1ra and the IL-1beta genes are not associated with osteoporotic fractures or alterations in bone mass or bone turnover.