Biomedical subjects
Publications and source records attributed to A Fryer.
A mother and daughter are reported with bilateral optic atrophy with onset in infancy and unilateral facial palsy. This appears to be a novel autosomal dominant disorder.
BACKGROUND: While cigarette smoking and chronic alcohol consumption are the major risk factors for the development of head and neck cancer, it is assumed that genetic factors contribute to risk. MATERIAL AND METHODS: We examined genotype frequencies from leukocyte DNA of 269 laryngeal cancer patients, 123 pharyngeal cancer patients and 216 controls. Polymorphisms at different glutathione-S-transferase (GST) gene loci were investigated. Losses of heterozygosity (LOH) at 12 different chromosomal gene loci were determined in 37 of the study patients by comparing blood and tumor cell DNA. The relationship between high risk genotypes and the occurrence of LOH was investigated. RESULTS: Glutathione-S-transferase high risk genotypes were identified at the first and third genes of the M family (GSTM1, GSTM3) and the first gene of the P family (GSTP1). These high risk genotypes are seen to have a statistically significant influence on the occurrence of LOH in the tumor tissue. CONCLUSION: There is evidence that the polymorphisms studied play a role in the carcinogenic process by influencing the chromosomal fragility which may lead to the inactivation of tumor suppressor genes or the activation of oncogenes.
While cigarette smoking and alcohol consumption are recognized covariates for head and neck squamous cell carcinoma (SCC), the role of genetic factors in determining individual susceptibility is unknown. The human tumour necrosis factor (TNF) region on chromosome 6p21 within the major histocompatibility complex (MHC) includes a number of immunologically important genes. Recently, five microsatellite markers have been described in the TNF locus. TNF levels vary with different TNF microsatellite alleles, and associations of these microsatellite markers with autoimmune diseases and different types of cancer have been shown. Therefore, the TNF locus represents candidate susceptibility genes for head and neck cancer. This study describes the influence of TNF a-d microsatellite polymorphisms on susceptibility to head and neck cancer by comparing the allele frequencies of 269 patients suffering from laryngeal cancer and 123 patients suffering from oral cavity pharyngeal cancer and 113 German controls. DNA was extracted from peripheral blood samples, amplified by polymerase chain reaction with fluorescently labelled primers for TNF microsatellite (a-d) and electrophoresed on polyacrylamide gels using an automated DNA sequencer. The data showed no differences in allele frequencies between controls and pharyngeal cancer patients. By contrast, the TNF b3 allele was associated with altered risk for laryngeal cancer (p = 0.0006, odds ratio 2.2). Homozygosity for TNF b3/b3 resulted in an increased risk of developing laryngeal cancer (p = 0.004, odds ratio 5.3). Susceptibility to supraglottic SCC and multiple primary tumours was mediated by the absence of the a11 allele. The data provide the first evidence that allelism at the TNF microsatellite markers alter the risk of developing SCC of the larynx.
Cerebral cavernous malformation (CCM) is a Mendelian model of stroke, characterized by focal abnormalities in small intracranial blood vessels leading to hemorrhage and consequent strokes and/or seizures. A significant fraction of cases is inherited as an autosomal dominant trait with incomplete penetrance. Among Hispanic Americans, virtually all CCM is attributable to a founder mutation localized to 7q ( CCM1 ). Recent analysis of non-Hispanic Caucasian kindreds, however, has excluded linkage to 7q in some, indicating at least one additional CCM locus. We now report analysis of linkage in 20 non-Hispanic Caucasian kindreds with familial CCM. In addition to linkage to CCM1, analysis of linkage demonstrates linkage to two new loci, CCM2 at 7p13-15 and CCM3 at 3q25.2-27. Multilocus analysis yields a maximum lod score of 14.11, with 40% of kindreds linked to CCM1, 20% linked to CCM2 and 40% linked to CCM3, with highly significant evidence for linkage to three loci (linkage to three loci supported with an odds ratio of 2.6 x 10(5):1 over linkage to two loci and 1.6 x 10(9):1 over linkage to one locus). Multipoint analysis among families with high posterior probabilities of linkage to each locus refines the locations of CCM2 and CCM3 to approximately 22 cM intervals. Linkage to these three loci can account for inheritance of CCM in all kindreds studied. Significant locus-specific differences in penetrance are identified. These findings have implications for genetic testing of this disorder and represent an important step toward identification of the molecular basis of this disease.
While cigarette smoking and alcohol consumption have been linked to laryngeal squamous cell carcinoma (SCC), the role of genetic factors in determining individual susceptibility is unknown. We describe the role of allelism at the glutathione S-transferase GSTM1, GSTM3, GSTT1 and cytochrome P450 CYP1A1, CYP2E1, CYP2D6 loci in determining individual susceptibility to laryngeal SCC. Enzyme genotypes were determined using polymerase chain reaction and restriction enzyme digestion of leukocyte DNA collected from 269 patients with T1-T4 laryngeal carcinomas and 216 controls. While the frequencies of the heterozygote GSTM1 A/B genotype and the homozygote GSTM3 B/B genotype were statistically significantly lower in the patients with tumors than in controls, the frequency of the GSTT1 null genotype was higher in the patients than in controls. The data suggest that allelism at GST loci mediates susceptibility to SCC of the larynx. GSTM1 A/B and GSTM3 B/B appear to be associated with reduced risk, while GSTT1 null may confer increased risk. These findings are compatible with the view that genetic predisposition is important in determining risk for this cancer.
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Most report of Weaver syndrome have been sporadic cases and the genetic basis of the syndrome is uncertain. This report of an affected father and daughter provides evidence for autosomal dominant inheritance.
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The trisomy 8 mosaic syndrome (Tr8MS), karyotype 46,XY/47,XY, +8, is a rare multisystem disorder that may be associated with corneal opacity. We report the case of a dysmorphic infant with multiple congenital abnormalities referred to our unit with a congenital corneal opacity. Subsequent chromosomal analysis of peripheral leucocytes demonstrated constitutional Tr8MS. At 4 years of age, lamellar keratoplasty was performed. Histological examination confirmed the lesion to be consistent with a corneal choristoma. Cytogenetic studies using in situ hybridisation techniques showed the presence of trisomic cells in cell culture derived from the tissue in higher proportion (92%) than in the blood (44%). Amplification of the c-myc oncogene on chromosome-8 could not be detected in cells cultured from the corneal lesion. Although not proof, these findings lend support to the concept of the corneal lesion representing a focus of viable trisomic cells rather than an inflammatory response to a nidus of effete cells.
We investigated whether tumor necrosis factor (TNF) microsatellite polymorphisms are associated with sex and age at disease onset in rheumatoid arthritis (RA). A case-control study was used to compare the frequencies of TNF microsatellite alleles in 181 Caucasian RA cases and 251 controls. TNF microsatellite genotyping was performed using fluorescent based polymerase chain reaction (PCR) techniques and HLA-DR typing using PCR based sequence specific oligonucleotide probing. The association of TNF microsatellite alleles a6, b5, and d4 with RA was confirmed. These polymorphisms were more frequent in female patients. Male patients with RA with young age at onset had a different TNF microsatellite profile, TNFa2, b1, and c2 being the most frequent. TNF microsatellite polymorphisms are different in male and female patients with RA. This difference was more obvious in patients stratified according to age at onset. Sex and age at onset should be considered in studies of genetic factors in RA.
Heparin has potential use as an antiinflammatory treatment in many lung diseases but its therapeutic use is limited by inherent anticoagulant activity. The anticoagulant nature of heparin can be eliminated by a number of chemical treatments, but often not without loss of other important pharmacological activities. Lyophilization of porcine mucosal heparin under extreme alkaline conditions (pH > or = 13) produces a nonanticoagulant heparin remarkable for the selective loss of only 2-O and 3-O sulfates, leaving 6-O and N-sulfates intact. In contrast to the commonly used nonanticoagulant analog N-desulfated, N-reacetylated heparin, selectively O-desulfated heparin retains potent activity as an inhibitor of the cationic neutrophil proteases human leukocyte elastase and cathepsin G, both in vitro and in vivo. Selectively O-desulfated heparin also inhibits complement lysis of erythrocytes, prevents ischemia-reperfusion injury of the lung, remains a potent antiproliferative treatment for cultured airway smooth muscle and normalizes altered neuronal M2 muscarinic receptor sensitivity and bronchial hyperreactivity after antigen challenge. These retained pharmacologic properties suggest possible use of this new nonanticoagulant heparin for the treatment of a variety of lung disorders.
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PURPOSE: While cigarette smoking and alcohol consumption are recognized covariates for laryngeal carcinoma, the role of genetic factors in determining individual susceptibility is unknown. We describe the influence of polymorphism in carcinogen-metabolizing enzymes on susceptibility to squamous cell carcinoma of the larynx. MATERIAL AND METHODS: We investigated 269 patients with T1-T4 laryngeal carcinoma and 216 controls. Enzyme genotypes at the glutathione-S-transferase GSTM1 (A, B, A/B, null), GSTM3 (A, B), GSTT1 (null and expressors), and cytochrome P-450, CYP2D6 (intron 3/exon 4 boundary mutation and exon 5 deletion), CYP1A1 (3'-mutation and exon 7 mutation), and CYP2E1 (mutation at the 5' flanking region) loci were determined using polymerase chain reaction and restriction-based approaches. RESULTS: While the frequencies of the heterozygote GSTM1 A/B and homocygote GSTM3 B/ B were statistically significantly lower in cases than controls, the frequency of the GSTT1 null genotype was higher in the cases than controls. Genotype frequencies of 123 patients suffering squamous cell carcinomas located at different sites within the upper aerodigestive tract showed no differences between cases and controls. CONCLUSIONS: The data provide evidence that susceptibility to laryngeal carcinoma, but not pharyngeal carcinoma, is mediated by allelism at a number of loci encoding enzymes involved in the detoxification of electrophils derived from environmental pollution including cigarette smoke.
The factors that determine development of single and multiple primary cutaneous basal cell carcinomas (BCCs) are unclear. We describe a case-control study firstly, to examine the influence of allelism at the glutathione S-transferase GSTM1 and GSTT1 and cytochrome P450 CYP2D6 loci on susceptibility to these tumours and, secondly, to identify interactions between genotypes and relevant individual characteristics, such as skin type and gender. Frequency distributions for GSTM1 genotypes in cases and controls were not different, although the frequency of GSTM1 A/B was significantly lower (P = 0.048) in the multiple BCCs than in controls. We found no significant differences in the frequencies of GSTT1 and CYP2D6 genotypes in cases and controls. Interactions between genotypes were studied by comparing multinomial frequency distributions in mutually exclusive groups. These identified no differences between cases and controls for combinations of the putatively high risk GSTM1 null, GSTT1 null, CYP2D6 EM genotypes. Interactions between GSTM1 A/B and the CYP2D6 PM and GSTT1-positive genotypes were also not different. Frequency distributions of GSTM1 A/B with CYP2D6 EM in controls and multiple BCCs were significantly different (P = 0.033). The proportion of males in the multiple BCC group (61.3%) was greater than in controls (47.0%) and single BCC (52.2%), and the frequency of the combination GSTM1 null/male gender was significantly greater in patients with multiple tumours (P = 0.002). Frequency distributions of GSTM1 null/skin type 1 were also significantly different (P = 0.029) and the proportion of subjects who were GSTM1 null with skin type 1 was greater (P = 0.009) in the multiple BCC group. We examined the data for interactions between GSTM1 null/skin type 1/male gender by comparing frequency distributions of these factors in the single and multiple BCC groups. The distributions were almost significantly different (exact P = 0.051). No significant interactions between GSTT1 null or CYP2D6 EM and skin type 1 were identified. Comparisons of frequency distributions of smoking with the GSTM1 null, GSTT1 null and CYP2D6 EM genotypes identified no differences between patients with single and multiple tumours.
A family is reported with two affected male siblings with features compatible with Filippi syndrome. These siblings are distinctive in having minimal developmental problems compared to the previously reported cases.
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There are a large number of well recognised syndromes comprising cerebellar ataxia in association with other neurological features. We report three family members who presented with a relapsing, early onset cerebellar ataxia, associated with progressive optic atrophy and sensorineural deafness. All three patients have areflexia (in the absence of a peripheral neuropathy), a pes cavus deformity, and show varying degrees of severity. Extensive neurological investigations have been normal, and the aetiology and pathophysiology of this disorder remain unclear. This may represent a separate syndrome of early onset cerebellar ataxia with associated features ("cerebellar ataxia plus"), which is likely to either have an autosomal dominant or maternal mitochondrial pattern of inheritance. The recognition of this association under the acronym of CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural deafness) may help in the delineation of a new syndrome.