Genetic investigation in an Italian child with an unusual association of atrial septal defect, attributable to a new familial GATA4 gene mutation, and neonatal diabetes due to pancreatic agenesis.

AIMS: Permanent neonatal diabetes is a rare condition affecting 1 in 300,000-400,000 live births; only in 60% of cases it is possible to identify the genetic defect. The condition of pancreatic agenesis is rarer still. Only two genes are known to determine this phenotype: PDX-1 and PTF1A. Congenital heart defects are among the most common developmental anomalies, affecting 1% of newborns, and the GATA4 gene is less frequently involved in these disorders. An Italian child with pancreatic agenesis and an atrial septal defect was genetically investigated to elucidate whether the association of the two pathologies was casual, or represented a new pancreatic/cardiac syndrome. METHODS: A panel of pancreas development genes, including GCK, Kir6.2, PTF1A, PDX-1, HNF-1A, NgN3, SOX17, SOX7, SOX9, INS, HNF1-B and SUR1 plus the GATA4 gene, were screened for characterization of pancreatic agenesis and cardiac defect. RESULTS: Screening for genes causing permanent neonatal diabetes was negative. A novel mutation in GATA4 (c1512C>T) was detected and functional characterization confirmed a reduced activity of the protein. In the family members, the GATA4 mutation co-segregates with a cardiac phenotype, but not with pancreatic agenesis. CONCLUSIONS: We describe the first report of pancretic agenesis with an associated cardiac defect and a mutation in the GATA4 gene. We could not establish that the GATA4 mutation was causative for pancreatic agenesis and further genetic investigation to detect the genetic cause of the pancreas agenesis was unsuccessful. We conclude that, the two pathologies are attributable to two independent events.

A polymorphic variant inside the osteopontin gene shows association with disease course in oligoarticular juvenile idiopathic arthritis.

BACKGROUND: Oligoarticular onset juvenile idiopathic arthritis (JIA) has a variable disease course. In some patients the disease remains confined to a few joints (persistent oligoarticular) while in others it extends to affect more joints (oligoarticular extended). Osteopontin is thought to play a role in the pathogenesis. OBJECTIVE: To investigate whether a polymorphic variant in the human osteopontin gene, which is in linkage disequilibrium with recently characterised promoter variants, is associated with the disease course in oligoarticular JIA. METHODS: Genotyping of the two base pair insertion/deletion variant at +245 in the first intron was undertaken by polymerase chain reaction (PCR) amplification of DNA fragments, using a fluorescently labelled primer, followed by allele detection after rapid separation of PCR products on an automated DNA sequencer. RESULTS: Allele 2 of the polymorphic variant in the osteopontin first intron was significantly associated with the persistent oligoarticular form rather than the extended form of JIA. This was verified at the level of genotype and allele frequencies. CONCLUSIONS: The results suggest that osteopontin gene polymorphism is associated with the disease course in oligoarticular JIA and might therefore represent a useful genetic marker to characterise patients with oligoarticular JIA who are at risk of a worse outcome.

Two single-nucleotide polymorphisms in the 5' and 3' ends of the osteopontin gene contribute to susceptibility to systemic lupus erythematosus.

OBJECTIVE: To test the association of osteopontin (OPN) polymorphisms with systemic lupus erythematosus (SLE). METHODS: The coding 5' and 3' flanking regions of the OPN gene were scanned for polymorphisms by denaturing high-performance liquid chromatography. A case-control association study was performed in 394 Italian SLE patients and 479 matched controls. OPN serum levels were determined by enzyme-linked immunosorbent assay in 40 patients and 124 controls, and the mean levels were compared between the different OPN genotypes. RESULTS: Among the 13 detected single-nucleotide polymorphisms (SNPs), alleles -156G (frequency 0.714 versus 0.651; P = 0.006, corrected P [P(corr)] = 0.036) and +1239C (0.377 versus 0.297; P = 0.00094, P(corr) = 0.0056) were significantly increased in the SLE patients compared with the controls. The presence of the associated allele in single or double dose conferred an odds ratio (OR) of 2.35 (95% confidence interval [95% CI] 1.38-4.02) for SNP -156 and an OR of 1.57 (95% CI 1.16-2.13) for SNP +1239. These effects were independent of each other, i.e., not a consequence of linkage disequilibrium between the 2 alleles. The risk associated with a double dose of susceptibility alleles at both SNPs was 3.8-fold higher (95% CI 2.0-7.4) relative to the complete absence of susceptibility alleles. With regard to individual clinical and immunologic features, a significant association was seen between lymphadenopathy and -156 genotypes (overall P = 0.0011, P(corr) = 0.046). A significantly increased OPN serum level was detected in healthy individuals carrying +1239C (P = 0.002), which is indicative of an association between the SLE susceptibility allele and OPN levels. CONCLUSION: These data suggest the independent effect of a promoter (-156) and a 3'-untranslated region (+1239) SNP in SLE susceptibility. We can speculate that these sequence variants (or others in perfect linkage disequilibrium) create a predisposition to high production of OPN, and that this in turn may confer susceptibility to SLE.

Genetic polymorphism of the renin-angiotensin system and organ damage in essential hypertension.

BACKGROUND: The renin-angiotensin-aldosterone system (RAAS) plays a significant role in the development of hypertensive cardiac and vascular remodeling. Recently, several genetic variants of its key components, which may be clinically relevant and thus prove to be useful in the evaluation of cardiovascular risk, have been described. We therefore investigated the association between ACE I/D, AGT M235T, and AT1 A1266C gene polymorphisms and early signs of target organ damage in 215 untreated patients with essential hypertension (EH). METHODS: Genotyping was based on the polymerase chain reaction technique, with further restriction analysis when required. Albuminuria was measured as the albumin-to-creatinine ratio (ACR). The left ventricular mass index (LVMI) was assessed by echocardiography (LVH = LVMI > or = 125 g/m2), carotid wall thickness (IMT) by an ultrasonographic (US) scan, and retinal vascular changes by direct ophthalmoscopy (Keith-Wagener classification). RESULTS: The prevalence of microalbuminuria (Mi), LVH, and retinal vascular changes was 14, 46, and 74%, respectively. ACE, AGT, and AT1 genotype distribution was in agreement with the Hardy-Weinberg equilibrium. There was no difference in age, duration of disease, body mass index (BMI), blood pressure, and lipid profile when data were analyzed on the basis of genotype. Serum levels of angiotensin-converting enzyme (ACE) were related to the ACE genotype (10.2 +/- 0.5, DD; 8.2 +/- 0.3, ID; 6.5 +/- 0.4 IU/mL, II; P < 0. 0001 by analysis of variance). The ACE genotype independently influences serum ACE levels and accounts for approximately 14% of its variations (F = 26.7, r2 = 0.1393, df 1 to 214, P < 0.0001). Patients with DD and ID genotypes showed higher levels of ACR (1.59 +/- 0.2, DD + ID; 0.8 +/- 0.2 mg/mmol, II; P < 0.006 by ANOVA) and bigger LVMI (124.1 +/- 2.3, DD + ID vs. 117.8 +/- 3.6 g/m2, II; P < 0.01 by ANOVA). No differences in the prevalence and degree of target organ damage (TOD) were found when data were analyzed on the basis of the AGT and AT1 genotypes, respectively. Potentially unfavorable combinations of genotypes were also investigated by K-means cluster analysis. Two subgroups of patients were identified (cluster 1, N = 70; cluster 2, N = 57), and each differed significantly with regards to the presence and degree of TOD and patterns of RAAS gene polymorphisms (F, 15.97 for ACR; F, 7.19 for IMT; F, 217.03 for LVMI; F, 3.91 for ACE; F, 4.06 for AGT; and F, 5. 22 for AT1; df 1 to 214, P < 0.02, for each one of the variables examined). CONCLUSION: The D allele of the ACE gene may be an independent risk factor for the development of target organ damage, and evaluating it could be useful for assessing cardiovascular risk in EH. Unfavorable patterns of RAAS genotypes seem to predispose patients to subclinical cardiovascular disease in EH.