Unraveling the disease pathogenesis behind lethal hydrolethalus syndrome revealed multiple changes in molecular and cellular level.

BACKGROUND: Hydrolethalus syndrome (HLS) is a severe fetal malformation syndrome characterized by multiple developmental anomalies, including central nervous system (CNS) malformation such as hydrocephaly and absent midline structures of the brain, micrognathia, defective lobation of the lungs and polydactyly. Microscopically, immature cerebral cortex, abnormalities in radial glial cells and hypothalamic hamartoma are among key findings in the CNS of HLS fetuses. HLS is caused by a substitution of aspartic acid by glycine in the HYLS1 protein, whose function was previously unknown. RESULTS: To provide insight into the disease mechanism(s) of this lethal disorder we have studied different aspects of HLS and HYLS1. A genome-wide gene expression analysis indicated several upregulated genes in cell cycle regulatory cascades and in specific signal transduction pathways while many downregulated genes were associated with lipid metabolism. These changes were supported by findings in functional cell biology studies, which revealed an increased cell cycle rate and a decreased amount of apoptosis in HLS neuronal progenitor cells. Also, changes in lipid metabolism gene expression were reflected by a significant increase in the cholesterol levels of HLS liver tissues. In addition, based on our functional studies of HYLS1, we propose that HYLS1 is a transcriptional regulator that shuffles between the cytoplasm and the nucleus, and that when HYLS1 is mutated its function is significantly altered. CONCLUSION: In this study, we have shown that the HYLS1 mutation has significant consequences in the cellular and tissue levels in HLS fetuses. Based on these results, it can be suggested that HYLS1 is part of the cellular transcriptional regulatory machinery and that the genetic defect has a widespread effect during embryonic and fetal development. These findings add a significant amount of new information to the pathogenesis of HLS and strongly suggest an essential role for HYLS1 in normal fetal development.

Hydrolethalus syndrome: neuropathology of 21 cases confirmed by HYLS1 gene mutation analysis.

Hydrolethalus syndrome is a lethal malformation syndrome with a severe brain malformation, most often hydrocephaly and absent midline structures. Other frequent findings are micrognathia, polydactyly, and defective lobation of the lungs. Hydrolethalus syndrome is inherited in an autosomal recessive manner and is caused by a missense mutation in the HYLS1 gene. Here, we report the neuropathologic features of 21 genetically confirmed cases. Typically, 2 separated cerebral hemispheres could be identified, but they lacked midline and olfactory structures and were situated basally with a massive accumulation of cerebrospinal fluid. Temporal and occipital lobes were hypoplastic, and normally developed hippocampi were not found. Primitive thalami and basal ganglia were fused in the midline. A hypothalamic hamartoma was a frequent finding, and brainstem and cerebellum were hypoplastic. Three cases were hydranencephalic, and 1 was anencephalic. A midline "keyhole" defect in the skull base was a constant finding. Histologically, the cortex was dysplastic. This pattern of brain pathology, clearly belonging to the midline patterning defects, seems to be unique for the hydrolethalus syndrome and combines features of disturbed neurulation, prosencephalization, and migration. Despite variation in the clinicopathologic phenotype, all cases in the series carried the same homozygous missense mutation in HYLS1.

Identification of CC2D2A as a Meckel syndrome gene adds an important piece to the ciliopathy puzzle.

Meckel syndrome (MKS) is a lethal malformation disorder characterized classically by encephalocele, polycystic kidneys, and polydactyly. MKS is also one of the major contributors to syndromic neural tube defects (NTDs). Recent findings have shown primary cilia dysfunction in the molecular background of MKS, indicating that cilia are critical for early human development. However, even though four genes behind MKS have been identified to date, they elucidate only a minor proportion of the MKS cases. In this study, instead of traditional linkage analysis, we selected 10 nonrelated affected fetuses and looked for the homozygous regions shared by them. Based on this strategy, we identified the sixth locus and the fifth gene, CC2D2A (MKS6), behind MKS. The biological function of CC2D2A is uncharacterized, but the corresponding polypeptide is predicted to be involved in ciliary functions and it has a calcium binding domain (C2). Immunofluorescence staining of patient's fibroblast cells demonstrates that the cells lack cilia, providing evidence for the critical role of CC2D2A in cilia formation. Our finding is very significant not only to understand the molecular background of MKS, but also to obtain additional information about the function of the cilia, which can help to understand their significance in normal development and also in other ciliopathies, which are an increasing group of disorders with overlapping phenotypes.

MKS1, encoding a component of the flagellar apparatus basal body proteome, is mutated in Meckel syndrome.

Meckel syndrome (MKS) is a severe fetal developmental disorder reported in most populations. The clinical hallmarks are occipital meningoencephalocele, cystic kidney dysplasia, fibrotic changes of the liver and polydactyly. Here we report the identification of a gene, MKS1, mutated in MKS families linked to 17q. Mks1 expression in mouse embryos, as determined by in situ hybridization, agrees well with the tissue phenotype of MKS. Comparative genomics and proteomics data implicate MKS1 in ciliary functions.

Polyphenol-rich phloem enhances the resistance of total serum lipids to oxidation in men.

In humans, polyphenol supplementation studies have resulted in inconsistent findings in lipid peroxidation. Our aim was to investigate the effects of a 4-week consumption of polyphenol-rich phloem on serum lipids and lipid peroxidation in the hydrophilic fraction of serum and on isolated lipoproteins. We conducted a randomized double-blind supplementation study consisting of 75 nonsmoking hypercholesterolemic men. Participants consumed 70 g daily of either rye bread (placebo) or phloem-fortified rye bread containing 31 mg (low polyphenol, LP) or 62 mg (high polyphenol, HP) of catechins. The ex vivo susceptibility of total serum lipids and VLDL and LDL to oxidation after copper induction was measured as a lag time to the maximal oxidation rate at the baseline and after the supplementation. In the HP group, an increase in the oxidation resistance of total serum lipids was observed (11.4%), while no effect was seen in the LP group (-0.8%) or in the placebo group (-1.0%) (p = 0.007). No differences were observed in the oxidation resistance of VLDL and LDL between the study groups. The phloem also increased in vitro oxidation resistance of serum lipids and radical scavenging activity (DPPH.) in a dose-dependent manner. Our results suggest that polyphenols may inhibit lipid peroxidation in the hydrophilic fraction of serum.

Hydrolethalus syndrome is caused by a missense mutation in a novel gene HYLS1.

Hydrolethalus syndrome (HLS) is an autosomal recessive lethal malformation syndrome characterized by multiple developmental defects of fetus. We have earlier mapped and restricted the HLS region to a critical 1 cM interval on 11q23-25. The linkage disequilibrium (LD) and haplotype analyses of single nucleotide polymorphism (SNP) markers helped to further restrict the HLS locus to 476 kb between genes PKNOX2 and DDX25. An HLS associated mutation was identified in a novel regional transcript (GenBank accession no. FLJ32915), referred to here as the HYLS1 gene. The identified A to G transition results in a D211G change in the 299 amino acid polypeptide with unknown function. The HYLS1 gene shows alternative splicing and the transcript is found in multiple tissues during fetal development. In situ hybridization shows spatial and temporal distributions of transcripts in good agreement with the tissue phenotype of HLS patients. Immunostaining of in vitro expressed polypeptides from wild-type (WT) cDNA revealed cytoplasmic staining, whereas mutant polypeptides became localized in distinct nuclear structures, implying a disturbed cellular localization of the mutant protein. The Drosophila melanogaster model confirmed these findings and provides evidence for the significance of the mutation both in vitro and in vivo.

Two-stage ultrasonography in screening for fetal anomalies at 13-14 and 18-22 weeks of gestation.

BACKGROUND: The aim of this study was to assess the value of two-stage screening by ultrasonography in detecting selected major fetal anomalies in a low-risk obstetric population. METHODS: In a defined geographic area, 4789 consecutive low-risk pregnant women participated in screening by two-stage ultrasonography as part of routine maternal care. The examinations were usually performed by specially trained midwives at 13-14 and 18-22 weeks of gestation. Of the women, 4073 had both scans, 440 had the early one only, and 276 the late scan only. Pregnancy outcomes were ascertained from obstetric and pediatric records, and the data were supplemented with information from the national birth and malformation registries. RESULTS: Of the 4855 fetuses, 33 (0.7%) had major structural defects considered detectable by ultrasonography. Of these, six (18%) were identified at the early scan, and an additional 10 (30%) at the late scan, yielding a total sensitivity of 48% for the two-stage screening. Twenty offspring had chromosomal abnormalities; 10 were identified by increased nuchal translucency at the early scan, one additional one (by hydronephrosis) at the late scan, and the remaining nine at birth. CONCLUSIONS: In a low-risk population, first-trimester scanning is useful in finding fetuses with chromosomal anomalies, but a second-trimester scan is needed for other types of defects. The sensitivity of routine screening by midwives for fetal structural defects in a general obstetric population remains lower than that reported by specialized centers.

Systolic blood pressure during recovery from exercise and the risk of acute myocardial infarction in middle-aged men.

We prospectively assessed the association of systolic blood pressure (SBP) after exercise with the risk of an acute myocardial infarction. Limited information exists currently on the role of SBP during recovery period with the risk of acute myocardial infarction. SBP was measured every 2 minutes during and after a progressive cycle ergometer exercise test in a representative sample of 2336 men (aged 42 to 61 years). During an average follow-up period of 13.1 years, 358 acute myocardial infarctions occurred. An incremental rise of 10 mm Hg per minute in SBP at 2 minutes after exercise (relative risk, 1.07-fold; 95% confidence interval [CI], 1.03 to 1.12; P=0.001) was associated with the risk of acute myocardial infarction after adjustment for age, alcohol consumption, smoking, serum lipids, diabetes mellitus, body mass index, resting SBP, regular use of antihypertensive medications, physical fitness, heart rate, and ischemic ECG findings during exercise. Men with elevated SBP of >195 mm Hg after exercise had a 1.69-fold (95% CI, 1.24 to 2.30; P=0.001) risk for an acute myocardial infarction compared with those with SBP <170 mm Hg after adjustment for age, other risk factors, and resting SBP. SBP after exercise provides an incremental predictive value for acute myocardial infarction beyond that of resting SBP. This emphasizes the importance of SBP measurements after the exercise test because it provides additional valuable prognostic measure with regard to acute myocardial infarction.

Inflammation, abdominal obesity, and smoking as predictors of hypertension.

Development of hypertension has been linked to chronic low-grade inflammation. However, it is not known whether this connection is mediated by features of the metabolic syndrome or smoking, or their changes, which themselves have been linked to inflammation. We studied the predictive value of highly sensitive C-reactive protein (hs-CRP), smoking, and abdominal obesity to the development of hypertension in an 11-year follow-up of a population-based study cohort comprising 379 middle-aged normotensive men. During the follow-up, 124 men (33%) developed hypertension. Men with hs-CRP > or =3.0 mg/L were 2.8x (95% confidence interval, 1.2 to 6.6) more likely to develop hypertension than with hs-CRP <1.0 mg/L even after adjustment for features of the metabolic syndrome, lifestyle factors, and their changes. Cigarette smoking was also associated with development of hypertension independently of inflammation and other confounders. Waist girth increased more in men who quit smoking than in other men. An increase in waist girth during follow-up strongly predicted incident hypertension. The decrease in smoking was not associated with a lower risk of hypertension in age-adjusted analyses. Hypertension is preceded by low-grade chronic inflammation in middle-aged white men independently of smoking or features of the metabolic syndrome. Furthermore, smoking may be a risk factor for hypertension. Although stopping smoking is beneficial with respect to health outcomes, the subsequent increase in weight and waist girth associated with smoking cessation may offset the decrease in the risk of hypertension that one may otherwise expect.

The predictive value of cardiorespiratory fitness for cardiovascular events in men with various risk profiles: a prospective population-based cohort study.

AIMS: Few data exist to show if the prognostic value of peak exercise oxygen consumption (VO2peak) for fatal and non-fatal coronary events is different among men with low and high pre-test probability for cardiovascular disease (CVD). Our objective was to determine whether VO2peak could predict fatal and non-fatal cardiac events in 2361 men aged 42-60 years with and without conventional risk predictors of CVD or with documented CVD during a 13-year follow-up. METHODS AND RESULTS: Maximal oxygen consumption (ml/kg/min) was measured directly by using respiratory gas exchange in a cycle ergometer exercise test. Of 204 CVD deaths, 153 were due to coronary disease and 51 were due to other CVDs. A total of 323 non-fatal coronary events occurred during the follow-up. One metabolic equivalent (MET) increment in VO2peak was related to a decreased risk of coronary death in both healthy (RR=0.82, 95% CI 0.66-0.99) and unhealthy (RR=0.72, 95% CI 0.63-0.82) men. VO2peak was predictive of non-fatal and fatal cardiac events among men with or without known risk factors. In subjects with or without common risk factors, one MET increment amounted to an average decrease of 17-29% in non-fatal and 28-51% in fatal cardiac events, after adjustment for age. VO2peak and smoking represented two strongest independent and consistent risk predictors. CONCLUSIONS: VO2peak can be used as a very powerful predictor of future fatal cardiac events beyond that predicted by many conventional risk factors. On the prognostic consideration, unfit men with unfavourable risk profiles or underlying chronic disease are the risk groups that will benefit most from preventive measures.

Testosterone and sex hormone-binding globulin predict the metabolic syndrome and diabetes in middle-aged men.

OBJECTIVE: In men, hypoandrogenism is associated with features of the metabolic syndrome, but the role of sex hormones in the pathogenesis of the metabolic syndrome and diabetes is not well understood. We assessed the association of low levels of testosterone and sex hormone-binding globulin (SHBG) with the development of the metabolic syndrome and diabetes in men. RESEARCH DESIGN AND METHODS: Concentrations of SHBG and total and calculated free testosterone and factors related to insulin resistance were determined at baseline in 702 middle-aged Finnish men participating in a population-based cohort study. These men had neither diabetes nor the metabolic syndrome. RESULTS: After 11 years of follow-up, 147 men had developed the metabolic syndrome (National Cholesterol Education Program criteria) and 57 men diabetes. Men with total testosterone, calculated free testosterone, and SHBG levels in the lower fourth had a severalfold increased risk of developing the metabolic syndrome (odds ratio [OR] 2.3, 95% CI 1.5-3.4; 1.7, 1.2-2.5; and 2.8, 1.9-4.1, respectively) and diabetes (2.3, 1.3-4.1; 1.7, 0.9-3.0; and 4.3, 2.4-7.7, respectively) after adjustment for age. Adjustment for potential confounders such as cardiovascular disease, smoking, alcohol intake, and socioeconomic status did not alter the associations. Factors related to insulin resistance attenuated the associations, but they remained significant, except for free testosterone. CONCLUSIONS: Low total testosterone and SHBG levels independently predict development of the metabolic syndrome and diabetes in middle-aged men. Thus, hypoandrogenism is an early marker for disturbances in insulin and glucose metabolism that may progress to the metabolic syndrome or frank diabetes and may contribute to their pathogenesis.

Learning curve in ultrasonographic screening for selected fetal structural anomalies in early pregnancy.

OBJECTIVE: To assess the value of first trimester screening by ultrasonography in detecting structural anomalies of the fetus in a general obstetric population. METHODS: During 1993-1998, 20,465 consecutive pregnant women who resided in a defined geographic area participated in ultrasonographic screening for major malformations. These included anomalies of the central nervous system, urinary tract, abdominal wall, and long bones. Heart anomalies were not expected to be detected. The examinations were offered at 13-14 weeks' gestation as part of routine maternal care and were done by specially trained midwives. The pregnancy outcomes were ascertained from obstetric and pediatric records, and the data were completed by information from the national birth and malformation registries. RESULTS: A total of 307 fetuses (1.5%) with a major malformation were found; 67 fetuses (0.3%) had noncardiac major structural defects expected to be detectable by ultrasonography in early pregnancy. Thirty-five of 67 (52%) were identified at the early scan. Sensitivity for these defects increased from 22% to 79% from the first to the last (sixth) study year (P =.009). CONCLUSION: In a low-risk population, adequate sensitivity in screening for major malformations by early ultrasonography can be achieved after a learning curve of 3-4 years.

Six-year effect of combined vitamin C and E supplementation on atherosclerotic progression: the Antioxidant Supplementation in Atherosclerosis Prevention (ASAP) Study.

BACKGROUND: Self-selected supplementation of vitamin E has been associated with reduced coronary events and atherosclerotic progression, but the evidence from clinical trials is controversial. In the first 3 years of the ASAP trial, the supplementation with 136 IU of vitamin E plus 250 mg of slow-release vitamin C twice daily slowed down the progression of carotid atherosclerosis in men but not women. This article examines the 6-year effect of supplementation on common carotid artery (CCA) intima-media thickness (IMT). METHODS AND RESULTS: The subjects were 520 smoking and nonsmoking men and postmenopausal women aged 45 to 69 years with serum cholesterol > or =5.0 mmol/L (193 mg/dL), 440 (84.6%) of whom completed the study. Atherosclerotic progression was assessed ultrasonographically. In covariance analysis in both sexes, supplementation reduced the main study outcome, the slope of mean CCA-IMT, by 26% (95% CI, 5 to 46, P=0.014), in men by 33% (95% CI, 4 to 62, P=0.024) and in women by 14% (not significant). In both sexes combined, the average annual increase of the mean CCA-IMT was 0.014 mm in the unsupplemented and 0.010 mm in the supplemented group (25% treatment effect, 95% CI, 2 to 49, P=0.034). In men, this treatment effect was 37% (95 CI, 4 to 69, P=0.028). The effect was larger in subjects with either low baseline plasma vitamin C levels or CCA plaques. Vitamin E had no effect on HDL cholesterol. CONCLUSIONS: These data replicate our 3-year findings confirming that the supplementation with combination of vitamin E and slow-release vitamin C slows down atherosclerotic progression in hypercholesterolemic persons.

Prenatally detected trisomy 7 mosaicism in a dysmorphic child.

Trisomy 7 mosaicism was detected prenatally in cultured amniocytes but not in fetal lymphocytes. The child that was born had pigmentary changes of the skin and facial asymmetry suggestive of a chromosomal mosaicism. Skin fibroblasts were studied and trisomy 7 mosaicism was confirmed. At 3 years of age the boy had developed mentally within normal limits. However, dysmorphic findings include sparse hair, short left palpebral fissure, ptosis of the left eyelid, strabismus, enamel dysplasia, low-set and posteriorly rotated ears and undescended testes. These findings share some common features with previously reported cases of trisomy 7 mosaicism.

Carotid artery intima-media thickness in Finnish families with familial combined hyperlipidemia.

BACKGROUND: Familial combined hyperlipidemia (FCHL) is the most common hereditary lipid disorder that predisposes the patients to premature coronary heart disease. Members of FCHL families are categorised as affected or unaffected according to serum lipid levels. This study is aimed to evaluate whether there is a difference in carotid artery wall thickness between asymptomatic FCHL family members who are affected and those who are unaffected according to the currently used lipid criteria. METHODS AND RESULTS: Carotid artery ultrasonography with intima-media thickness (IMT) measurements was performed for 148 members of 39 Finnish FCHL families. Study subjects who had no history of coronary heart disease or stroke were divided into two groups according to their serum total cholesterol and/or triglyceride levels. The average carotid IMT of the affected subjects (0.75+/-0.15 mm) was not significantly different from that of their unaffected relatives (0.73+/-0.13 mm), P=0.90. In multivariate analysis, age, gender, and pulse pressure, but no lipid variables, contributed significantly to the variation of carotid IMT. CONCLUSIONS: The IMT findings in FCHL family members indicate that the current lipid criteria alone are of limited value in predicting long-term risk of cardiovascular disease in asymptomatic members of FCHL families.