Truncated human endothelin receptor A produced by alternative splicing and its expression in melanoma

In this study, reverse transcriptase polymerase chain reaction was used to amplify human endothelin receptor A (ETA) and ETB receptor mRNA. A truncated ETA receptor transcript with exons 3 and 4 skipped was found. The skipping of these two exons results in 109 amino acids being deleted from the receptor. The truncated receptor was expressed in all tissues and cells examined, but the level of expression varied. In melanoma cell lines and melanoma tissues, the truncated receptor gene was the major species, whereas the wild-type ETA was predominant in other tissues. A 1.9-kb ETA transcript was identified in melanoma cell lines by Northern blot, which was much smaller than the transcript in heart and in other tissues reported previously (4.3 kb). The cDNA coding regions of the truncated and wild-type ETA receptors were stably transfected into Chinese hamster ovary (CHO) cells. The truncated ETA receptor-transfected CHO cells did not show binding affinity to endothelin 1 (ET-1) or endothelin 3 (ET-3). The function and biological significance of this truncated ETA receptor is not clear, but it may have regulatory roles for cell responses to ETs.

Methylenetetrahydrofolate reductase polymorphism (C-677T) and coronary artery disease

1. Many studies have shown that hyperhomocysteinaemia is a risk factor for atherosclerotic vascular disease. A mutation (C-677T) in the gene coding for the methylenetetrahydrofolate reductase (MTHFR) enzyme has been shown to produce a thermolabile form of the enzyme. Homozygosity for this mutation has been correlated with an elevated plasma homocysteine concentration. The present study aimed to determine whether this mutation was a risk factor for coronary artery disease (CAD). This was achieved by comparing the frequency of the C-677T mutation in patients with angiographically proven CAD against angiographically normal patients in two separate U.K. samples. The analysis was repeated with CAD patients split into those with >=99% stenosis of arteries and those without, to establish whether the C-677T mutation could be correlated with severity of CAD.2. Two patient groups were selected from London and Sheffield. The London group comprised 174 cases and 148 controls. The Sheffield group comprised 93 cases and 85 controls. The DNA samples of the patients were genotyped by polymerase chain reaction and restriction enzyme digestion.3. For London the homozygous C-677T frequencies were: 0.07 (controls), 0.09 (CAD without >=99% stenosis) and 0.10 (CAD with >=99% stenosis). For Sheffield the homozygous C-677T frequencies were: 0.08 (controls), 0.10 (CAD without >=99% stenosis) and 0.11 (CAD with >=99% stenosis). No association was found between the C-677T mutation and CAD in our sample geographical groups. Statistical comparison by genotype distribution for 0 VD (no vessel disease, i.e. 0% diameter reduction in all epicardial arteries) versus CAD without >=99% stenosis: London, P=0.19; Sheffield, P=0.53; 0 VD versus CAD with >=99% stenosis: London, P=0. 23; Sheffield, P=0.55.

Apparent normalisation of fetal renal size in autosomal dominant polycystic kidney disease (PKD1)

We present a family with adult onset autosomal dominant polycystic kidney disease (ADPKD) in two generations, linked to the PKD1 locus and with paternal transmission to the fetus. The fetus carried the PKD1 haplotype and was, therefore a gene carrier. Progressive hyperechogenic renal enlargement, but no cysts, was documented by serial fetal ultrasounds at 21, 23 and 34 weeks of gestation. Surprisingly, the newborn renal scan showed normal sized kidneys with apparently normal corticomedullary differentiation. However, at 11 months of age, the evolution of cysts in one kidney, and then in the other kidney at 20 months, was documented by ultrasound in the absence of clinical symptoms or signs. The observed normalisation of fetal renal ultrasound appearances at birth has not previously been described in fetuses presenting with PKD1.

Localisation of the gene for glycogen storage disease type 1c by homozygosity mapping to 11q

The microsomal glucose-6-phosphatase (G6Pase) complex regulates the final step in glucose production from glycogenolysis and gluconeogenesis. Glycogen storage disease type 1c (GSD-1c) results from deficient activity of the phosphate/ pyrophosphate transporter of this complex and is associated with neutropenia as well as hepatomegaly and hypoglycaemia. Using three affected subjects from a single highly consanguineous family, we have used homozygosity mapping to localise the gene responsible for GSD-1c to a 10.2 cM region on 11q23.3-24.2. The maximum lod score was 3.12. GSD-1c is therefore distinct from GSD-1a, which has been shown previously to be caused by mutations in the G6Pase gene on chromosome 17.

Prenatal diagnosis of autosomal dominant polycystic kidney disease (PKD1) presenting in utero and prognosis for very early onset disease

We describe four prenatal diagnoses in a family with autosomal dominant polycystic kidney disease. Two pregnancies were terminated following the detection of enlarged echogenic fetal kidneys with cysts. Histopathological examination confirmed the diagnosis of polycystic kidney disease. Linkage to PKD1 was obtained by the analysis of DNA from relatives in three generations and from paraffin blocks and formalin fixed fetal tissues. Prenatal DNA analysis in subsequent pregnancies identified one unaffected fetus and one fetus carrying the high risk PKD1 allelle. Information on survival and subsequent outcome of PKD cases presenting in utero was requested by this family before prenatal testing was performed. Of 83 reported cases of ADPKD presenting in utero (excluding termination of pregnancy) or in the first few months of life, 43% died before 1 year. Longitudinal follow up of 24 children in two studies showed that 67% of survivors developed hypertension, of whom three had end stage renal failure at a mean age of 3 years.

Thrombotic thrombocytopenic purpura in a patient with genetic haemochromatosis, liver cirrhosis and an iron-free focus

We report a patient with thrombotic thrombocytopenic purpura and genetic haemochromatosis. The patient was shown by the polymerase chain reaction to be homozygous for the Cys282Tyr mutation of the HFE gene. Liver biopsy showed micronodular cirrhosis and the presence of an iron-free focus which was thought to be pre-neoplastic.

Polycystin expression during embryonic development of human kidney in adult tissues and ADPKD tissue

Normal renal tissue, ranging from 8 weeks' gestation to full term to adult, was probed with polyclonal antibodies raised to peptide epitopes within the translated PKD1 gene sequence. Three antibodies were studied, all of which gave similar results. Renal tissue from patients with autosomal dominant polycystic kidney disease (ADPKD) and samples from normal adult liver, heart, brain, skeletal muscle and lymph node were also studied. Tissue staining demonstrated that the pattern of polycystin expression changed with gestational age in normal kidney. Whereas the precursors to the renal excretory unit were stained at 12 weeks, and the proximal and distal convoluted tubules stained to differing degrees throughout development, the glomeruli were poorly stained until full term and also in the adult. Extrarenal tissue stained in both adult and juvenile samples, with the exception of lymph node, which remained unstained. The intensity of polycystin staining increased in ADPKD renal tissue. The widespread distribution of polycystin was consistent with the systemic nature of ADPKD and the role of epithelial cells in the disease.

Factor V Leiden polymorphism (FV Q506) in patients with ischaemic heart disease, and in different populations groups

A point mutation in the factor V gene (FV Q506) renders factor V resistant to inactivation by activated protein C. The frequency of this mutation is known to be significantly increased in patients with thrombophilia. There are conflicting reports on the significance of the polymorphism in patients with ischaemic heart disease. We determined the frequency of FV Q506 in a control Caucasian population, and compared it with 192 Caucasian patients admitted to coronary care and assessed as having myocardial infarction (MI) or unstable angina plus previous MI. There was no significant difference between the two groups. A cohort of 105 asymptomatic Afro-Caribbeans showed a much reduced frequency of the polymorphism.

Enteroviral pharyngitis diagnosed by reverse transcriptase-polymerase chain reaction

The role of enteroviruses in childhood pharyngitis was investigated using enteroviral specific reverse transcriptase-polymerase chain reaction (RT-PCR). Viral/bacterial throat swabs were taken from 50 children with acute pharyngitis and 26 controls. A positive culture was identified in only 26% of children with pharyngitis (adenovirus 10%, group A streptococci 2%), and none of the controls. Enteroviral RT-PCR was positive in 8% of the pharyngitis group and none of the controls. Enteroviruses are an important cause of pharyngitis in childhood.

Angiotensin-converting enzyme insertion/deletion polymorphism and restenosis after coronary angioplasty in unstable angina pectoris

We studied the relation between angiotensin-converting enzyme insertion/deletion gene polymorphism and restenosis in Caucasian patients who underwent coronary angioplasty for management of unstable angina pectoris. Our results indicate that, in contrast to previous reports in Japanese patients, no association exists between angiotensin-converting enzyme gene polymorphism and the development of restenosis in Caucasian patients with acute coronary syndromes.)

Genetic risk for renal artery stenosis: association with deletion polymorphism in angiotensin 1-converting enzyme gene

Atherosclerotic renal artery disease is an important secondary cause of hypertension. Currently, there is great interest in possible genetic determinants of cardiovascular disease. The ACE-D allele has been reported to be associated with increased risk of myocardial infarction as well as coronary re-stenosis after angioplasty. We therefore assessed whether this allele is also linked to renovascular disease by studying 56 Caucasian subjects with atherosclerotic renal artery stenosis and 74 age, sex and race matched control subjects. Genetic analysis for the ACE I/D polymorphism was performed on peripheral leukocytes using PCR techniques, including insertion-specific primers. The distribution of I and D alleles was: renal artery stenosis 8 II, 25 ID, 23 DD; and controls, 16 II, 41 ID, 17 DD. The frequency of the D allele in the renal artery stenosis group was significantly higher (D/total 71/112 = 0.66) than that of the control population [75/148 = 0.51; chi 2 = 4.17, P = 0.04; odds ratio 1.69 (95% CI 1.02 to 2.78)]. Our results suggest that the ACE-D allele may be associated with increased risk of vascular disease at sites other than the coronary circulation.

Epilepsy monitoring and advice recorded: general practitioners' views, current practice and patients' preferences

BACKGROUND

Epilepsy is a common condition that is managed at the interface between primary and secondary care.

AIM

A study aimed to describe general practitioners' criteria for aspects of optimal epilepsy care and their estimates of current levels of care achieved; to compare these estimates with clinical data extracted from their patients' medical records; and to compare general practitioners' estimates and recorded data with information provided by the patients themselves.

METHOD

Thirty seven general practitioners from six practices in the south Thames region were sent a questionnaire enquiring about current practice with regard to general practitioner and specialist monitoring of patients with epilepsy and provision of advice, and about their criteria for the optimum levels of aspects of epilepsy care. Of patients aged over 15 years in the study practices, 0.6% were found to have active epilepsy; 283 of these 326 patients were sent a questionnaire enquiring about their epilepsy, the service and advice provided, and whether they required more information. Responses to the general practitioners' questionnaire and to the patients' questionnaire were compared and also compared with information extracted from the patients' medical records.

RESULTS

Ninety five per cent of the general practitioners responded. Of 255 patient questionnaires (90%) returned, 251 could be analysed. Of 247 patients, 168 (68%) reported having had no seizure in the previous six months. Forty of 241 patients (17%) had a regular arrangement to see their general practitioner regarding their epilepsy. Of 191 patients who expressed a preference, 116 (61%) reported preferring to receive their epilepsy care mainly from their general practitioner. General practitioners reported that ideally patients should be monitored in primary care every six months (the median recorded frequency was 14 months) and that there should be a record of advice given to all patients on driving, adverse effects of antiepileptic drugs, and self-help groups. Advice was recorded in patients' records as having been given on driving (46% of records), adverse effects of antiepileptic drugs (9%), and self-help groups (3%); 82 of 237 patients (35%) reported not receiving enough advice.

CONCLUSION

Patients generally preferred to receive their epilepsy care in general practice. Monitoring and provision of advice were less than optimal from both the general practitioners' and the patients' point of view. New resources and skills will be necessary to bridge this perceived gap. Specially trained nurses may have a role in this monitoring and advice provision.

Angiotensin converting enzyme gene I/D polymorphism, blood pressure and the renin-angiotensin system in Caucasian and Afro-Caribbean peoples

The objectives of this study were to assess relations between ACE gene I/D polymorphism, essential hypertension, plasma renin activity and aldosterone in white (European descent) and black (Afro-Caribbean descent) peoples. Measurements were carried out on a total of 320 subjects (210 white: 116 men, 94 women; 110 black: 65 men, 45 women); all were on their usual sodium intake; none was on anti-hypertensive therapy and none had secondary hypertension. Genomic DNA was isolated from blood cells and ACE I/D genotype was established using polymerase chain reaction. Plasma hormones were measured by radioimmunoassay and blood pressure (BP) with an ultrasound sphygmomanometer. All subjects were grouped into normotensive, borderline and hypertensive according to WHO guidelines. The distribution of the I/D genotype in the white people was approximately 1:2:1; by contrast, in the Afro-Caribbean people there was a significantly higher frequency of the D allele (chi 2P = 0.04). Within the white people there was no significant association between ACE genotype and high BP; however, within the black people there was a positive association between the frequency of the D allele and increasing BP ( chi 2 for trend P = 0.03). In either group, there were no associations between ACE I/D genotype and plasma renin activity and aldosterone suggesting that ACE genotype does not contribute to the expression of the circulating renin-angiotensin system. This study highlights differences in ACE I/D polymorphism between white and black peoples and suggests the possibility of racial differences in the association between ACE genotype and BP.

Linkage analysis in blepharophimosis-ptosis syndrome confirms localisation to 3q21-24

Blepharophimosis-ptosis is an autosomal dominant disorder in which previous chromosome rearrangements have suggested a putative gene location on the long arm of chromosome 3. This paper confirms the location at 3q21-24 with linkage studies in two large families. A lod score of 3·2 was found with D3S1237.

Angiotensin-converting enzyme gene deletion polymorphism. A new risk factor for lacunar stroke but not carotid atheroma

BACKGROUND AND PURPOSE

A deletion (D)/insertion (I) polymorphism in the angiotensin-converting enzyme gene has been associated with myocardial infarction. Its relations to both stroke and atheroma remain uncertain. We examined its role as a risk factor in patients with cerebrovascular disease and its relation to carotid atheroma.

METHODS

One hundred one patients with symptomatic carotid artery territory cerebral ischemia were compared with 137 age-matched control subjects. In the patient group, carotid atheroma was assessed by measurement of degree of carotid stenosis and intima-media thickness with high-resolution duplex ultrasound. The D/I polymorphism was examined using the polymerase chain reaction.

RESULTS

D:I allele frequency was 0.59:0.41 in case subjects and 0.48:0.52 in control subjects (P = .01). The DD genotype was more common in patients with cerebrovascular disease compared with control subjects (36/101 versus 30/137, P = .02). The DD genotype conferred a relative risk of any type of cerebrovascular disease of 1.98 (95% confidence interval [CI], 1.11 to 3.51; P = .02). However, this was largely due to a strong association in the 18 patients with lacunar stroke, in whom the D:I ratio was 0.75:0.25 (P = .0097 versus control subjects). The odds ratio for lacunar stroke associated with the DD genotype was 5.6 (95% CI, 2.0 to 15.7) and was still significant at 4.40 (95% CI, 1.45 to 12.6; P < .009) after controlling for other risk factors. There was no significant association between angiotensin-converting enzyme genotype and cerebrovascular disease due to large-vessel stenosis. There was no association between genotype and age, sex, smoking history, diabetes, or cholesterol level.

CONCLUSIONS

The deletion polymorphism in the angiotensin-converting enzyme gene is a new independent risk factor for lacunar stroke but is not a risk factor for stroke associated with carotid stenosis.

Genetic analysis of 20 families with autosomal dominant adult polycystic kidney disease from South West Thames Region

Twenty families with autosomal dominant polycystic kidney disease from S. W. Thames Region were analysed using markers for chromosome 16p13.3, the site of the common mutation (PKD1). Six families gave a negative lod-score for 3'HVR, the most informative distal marker. This could be explained in four cases by recombination events. Of the two families where this was not an explanation, one, of Italian origin, was unequivocally unlinked for all markers, and the other was more likely to be non-PKD1 than linked to 16p13.3. The Italian family was ascertained through the Blood Pressure Unit, and the other via the Genetic Clinic. No members of either family had ever attended a renal clinic. The remaining 18 families either came via renal clinics, or had at least one member attending such a centre.

A family with autosomal dominant polycystic kidney disease linked to 4q21-23

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Mapping a gene for Noonan syndrome to the long arm of chromosome 12

Noonan syndrome is characterized by typical facies, short stature and congenital cardiac defects. Approximately half of all cases are sporadic, but autosomal dominant inheritance with variable expression is well established. We have performed a genome-wide linkage analysis in a large Dutch kindred with autosomal dominant Noonan syndrome, and localized the Noonan syndrome gene to chromosome 12 (Zmax = 4.04 at 0 = 0.0). Linkage analysis using chromosome 12 markers in 20 smaller, two-generation families gave Zmax = 2.89 at 0 = 0.07, but haplotype analysis showed non-linkage in one family. These data imply that a gene for Noonan syndrome is located on chromosome 12q, between D12S84 and D12S366.

Angiotensin converting enzyme insertion/deletion polymorphism: association with ethnic origin

OBJECTIVE

To determine the distribution of the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene in several ethnic groups: Caucasian Europeans, Black Nigerians, Samoan Polynesians and Yanomami Indians.

RESULTS

The ratio of the frequencies of the II, ID and DD genotypes were 1:2:1 in the Europeans, but there was a tendency towards a higher frequency of the D allele in the Nigerians. In contrast, the Samoans and the Yanomami Indians displayed a much higher frequency of the I allele than of the D allele.

CONCLUSION

The relationship between ACE genotype and disease in these latter groups is still not known, but the present results clearly suggest that ethnic origin should be carefully considered in the increasing number of studies on the association between I/D ACE genotype and disease aetiology.

Angiotensin-1 converting enzyme (ACE) polymorphism in patients presenting with myocardial infarction or unstable angina

A deletion/insertion polymorphism in the ACE gene has been reported previously as a potent factor for myocardial infarction. We have tested the frequency of the deletion (D) allele of the ACE gene in 308 consecutive patients admitted to coronary care with chest pain. The gene frequencies were compared with those of 348 controls recruited from the London area. Of 108 Caucasian patients with myocardial infarction, the DD genotype was found more frequently than the combined DI and II genotypes (Chi-square, chi 2 = 5.07, 2P = 0.024). The overall D gene frequency was higher in myocardial infarction patients (125 of 216, 58%) than in controls (347 of 696, 49.9%) (chi 2 = 3.79, 2P = 0.052). In contrast, the DD genotype and D allele frequencies in patients with unstable angina were similar to those found in our normal population. A nonsignificant difference in allele frequency between myocardial infarction and unstable angina patients was observed but the small numbers of subjects studied precludes a more formal comparison. Since unstable angina and myocardial infarction represent a spectrum of coronary thrombosis, it is possible that the DD genotype favours the development of myocardial infarction, perhaps through the presence of higher serum ACE concentrations.