Genetic causes of growth disorders

Growth in humans, primarily longitudinal growth, is a complex process which starts at conception and proceeds through various developmental stages, mainly controlled by genetic factors and to a lesser degree by environmental, psychosocial and nutritional factors. The GH-IGF-I axis is an important regulator of longitudinal growth, what is evident from the observation that genetic defects in this axis have been shown to be responsible for abnormal growth. These mutations, however, are rare and do not explain the __normal__ variation in height among people. This thesis focuses on the detection of genetic defects in the GH-IGF-I axis that may explain growth disorders. Initially the so-called __candidate gene approach__ was used, examining various genes in the GH-IGF-I axis. After that, a whole genome approach was used to identify novel genes involved in aberrant growth using whole genome microarray studies (SNP-ar rays) and next-generation sequencing. Also, for some genes genotype-phenotype correlations were established. With this we have tried to acquire more insight in the regulation of longitudinal growthUBL - phd migration 201

A Dietary Mixture Containing Fish Oil, Resveratrol, Lycopene, Catechins, and Vitamins E and C Reduces Atherosclerosis in Transgenic Mice123

Chronic inflammation and proatherogenic lipids are important risk factors of cardiovascular disease (CVD). Specific dietary constituents such as polyphenols and fish oils may improve cardiovascular risk factors and may have a beneficial effect on disease outcomes. We hypothesized that the intake of an antiinflammatory dietary mixture (AIDM) containing resveratrol, lycopene, catechin, vitamins E and C, and fish oil would reduce inflammatory risk factors, proatherogenic lipids, and endpoint atherosclerosis. AIDM was evaluated in an inflammation model, male human C-reactive protein (CRP) transgenic mice, and an atherosclerosis model, female ApoE*3Leiden transgenic mice. Two groups of male human-CRP transgenic mice were fed AIDM [0.567% (wt:wt) powder and 0.933% (wt:wt oil)] or placebo for 6 wk. The effects of AIDM on basal and IL-1β–stimulated CRP expression were investigated. AIDM reduced cytokine-induced human CRP and fibrinogen expression in human-CRP transgenic mice. In the atherosclerosis study, 2 groups of female ApoE*3Leiden transgenic mice were fed an atherogenic diet supplemented with AIDM [0.567% (wt:wt) powder and 0.933% (wt:wt oil)] or placebo for 16 wk. AIDM strongly reduced plasma cholesterol, TG, and serum amyloid A concentrations compared with placebo. Importantly, long-term treatment of ApoE*3Leiden mice with AIDM markedly reduced the development of atherosclerosis by 96% compared with placebo. The effect on atherosclerosis was paralleled by a reduced expression of the vascular inflammation markers and adhesion molecules inter-cellular adhesion molecule-1 and E-selectin. Dietary supplementation of AIDM improves lipid and inflammatory risk factors of CVD and strongly reduces atherosclerotic lesion development in female transgenic mice

Differential diagnosis of the short IGF-I-Deficient child with apparently normal growth hormone secretion

The current differential diagnosis for a short child with low insulin-like growth factor I (IGF-I) and a normal growth hormone (GH) peak in a GH stimulation test (GHST), after exclusion of acquired causes, includes the following disorders: (1) a decreased spontaneous GH secretion in contrast to a normal stimulated GH peak ("GH neurosecretory dysfunction," GHND) and (2) genetic conditions with a normal GH sensitivity (e.g., pathogenic variants of GH1 or GHSR) and (3) GH insensitivity (GHI). We present a critical appraisal of the concept of GHND and the role of 12- or 24-h GH profiles in the selection of children for GH treatment. The mean 24-h GH concentration in healthy children overlaps with that in those with GH deficiency, indicating that the previously proposed cutoff limit (3.0-3.2 mu g/L) is too high. The main advantage of performing a GH profile is that it prevents about 20% of false-positive test results of the GHST, while it also detects a low spontaneous GH secretion in children who would be considered GH sufficient based on a stimulation test. However, due to a considerable burden for patients and the health budget, GH profiles are only used in few centres. Regarding genetic causes, there is good evidence of the existence of Kowarski syndrome (due to GH1 variants) but less on the role of GHSR variants. Several genetic causes of (partial) GHI are known (GHR, STAT5B, STAT3, IGF1, IGFALS defects, and Noonan and 3M syndromes), some responding positively to GH therapy. In the final section, we speculate on hypothetical causes.Developmen

Preparing n-of-1 antisense oligonucleotide treatments for rare neurological diseases in Europe: genetic, regulatory, and ethical perspectives

Antisense oligonucleotide (ASO) therapies present a promising disease-modifying treatment approach for rare neurological diseases (RNDs). However, the current focus is on "more common" RNDs, leaving a large share of RND patients still without prospect of disease-modifying treatments. In response to this gap, n-of-1 ASO treatment approaches are targeting ultrarare or even private variants. While highly attractive, this emerging, academia-driven field of ultimately individualized precision medicine is in need of systematic guidance and standards, which will allow global scaling of this approach. We provide here genetic, regulatory, and ethical perspectives for preparing n-of-1 ASO treatments and research programs, with a specific focus on the European context. By example of splice modulating ASOs, we outline genetic criteria for variant prioritization, chart the regulatory field of n-of-1 ASO treatment development in Europe, and propose an ethically informed classification for n-of-1 ASO treatment strategies and level of outcome assessments. To accommodate the ethical requirements of both individual patient benefit and knowledge gain, we propose a stronger integration of patient care and clinical research when developing novel n-of-1 ASO treatments: each single trial of therapy should inherently be driven to generate generalizable knowledge, be registered in a ASO treatment registry, and include assessment of generic outcomes, which allow aggregated analysis across n-of-1 trials of therapy.Genetics of disease, diagnosis and treatmen

TGDS pathogenic variants cause Catel-Manzke syndrome without hyperphalangy

Catel-Manzke syndrome, also known as micrognathia-digital-syndrome, is a rare autosomal recessive disorder characterized by the combination of the two cardinal features Pierre-Robin sequence and bilateral hyperphalangy leading to ulnar clinodactyly (ulnar curvature of the phalanges) and radial deviation (radial angulation at the metacarpophalangeal joint) of the index finge

Propionic acid and not caproic acid, attenuates nonalcoholic steatohepatitis and improves (cerebro) vascular functions in obese Ldlr^−/−.Leiden mice

The obesity epidemic increases the interest to elucidate impact of short-chain fatty acids on metabolism, obesity, and the brain. We investigated the effects of propionic acid (PA) and caproic acid (CA) on metabolic risk factors, liver and adipose tissue pathology, brain function, structure (by MRI), and gene expression, during obesity development in Ldlr−/−.Leiden mice. Ldlr−/−.Leiden mice received 16 weeks either a high-fat diet (HFD) to induce obesity, or chow as reference group. Next, obese HFD-fed mice were treated 12 weeks with (a) HFD + CA (CA), (b) HFD + PA (PA), or (c) a HFD-control group. PA reduced the body weight and systolic blood pressure, lowered fasting insulin levels, and reduced HFD-induced liver macrovesicular steatosis, hypertrophy, inflammation, and collagen content. PA increased the amount of glucose transporter type 1-positive cerebral blood vessels, reverted cerebral vasoreactivity, and HFD-induced effects in microstructural gray and white matter integrity of optic tract, and somatosensory and visual cortex. PA and CA also reverted HFD-induced effects in functional connectivity between visual and auditory cortex. However, PA mice were more anxious in open field, and showed reduced activity of synaptogenesis and glutamate regulators in hippocampus. Therefore, PA treatment should be used with caution even though positive metabolic, (cerebro) vascular, and brain structural and functional effects were observed.</p

Evidence that non-syndromic familial tall stature has an oligogenic origin including ciliary genes

Human growth is a complex trait. A considerable number of gene defects have been shown to cause short stature, but there are only few examples of genetic causes of non-syndromic tall stature. Besides rare variants with large effects and common risk alleles with small effect size, oligogenic effects may contribute to this phenotype. Exome sequencing was carried out in a tall male (height 3.5 SDS) and his parents. Filtered damaging variants with high CADD scores were validated by Sanger sequencing in the trio and three other affected and one unaffected family members. Network analysis was carried out to assess links between the candidate genes, and the transcriptome of murine growth plate was analyzed by microarray as well as RNA Seq. Heterozygous gene variants in CEP104, CROCC, NEK1, TOM1L2, and TSTD2 predicted as damaging were found to be shared between the four tall family members. Three of the five genes (CEP104, CROCC, and NEK1) belong to the ciliary gene family. All genes are expressed in mouse growth plate. Pathway and network analyses indicated close functional connections. Together, these data expand the spectrum of genes with a role in linear growth and tall stature phenotypes.Genetics of disease, diagnosis and treatmen

Biallelic loss of LDB3 leads to a lethal pediatric dilated cardiomyopathy

Autosomal dominant variants in LDB3 (also known as ZASP), encoding the PDZ-LIM domain-binding factor, have been linked to a late onset phenotype of cardiomyopathy and myofibrillar myopathy in humans. However, despite knockout mice displaying a much more severe phenotype with premature death, bi-allelic variants in LDB3 have not yet been reported. Here we identify biallelic loss-of-function variants in five unrelated cardiomyopathy families by next-generation sequencing. In the first family, we identified compound heterozygous LOF variants in LDB3 in a fetus with bilateral talipes and mild left cardiac ventricular enlargement. Ultra-structural examination revealed highly irregular Z-disc formation, and RNA analysis demonstrated little/no expression of LDB3 protein with a functional C-terminal LIM domain in muscle tissue from the affected fetus. In a second family, a homozygous LDB3 nonsense variant was identified in a young girl with severe early-onset dilated cardiomyopathy with left ventricular non-compaction; the same homozygous nonsense variant was identified in a third unrelated female infant with dilated cardiomyopathy. We further identified homozygous LDB3 frameshift variants in two unrelated probands diagnosed with cardiomegaly and severely reduced left ventricular ejection fraction. Our findings demonstrate that recessive LDB3 variants can lead to an early-onset severe human phenotype of cardiomyopathy and myopathy, reminiscent of the knockout mouse phenotype, and supporting a loss of function mechanism

Therapeutic intervention with anti-complement component 5 antibody does not reduce nash but does attenuate atherosclerosis and mif concentrations in ldlr-/-.Leiden mice

Background: Chronic inflammation is an important driver in the progression of nonalcoholic steatohepatitis (NASH) and atherosclerosis. The complement system, one of the first lines of defense in innate immunity, has been implicated in both diseases. However, the potential therapeutic value of complement inhibition in the ongoing disease remains unclear. Methods: After 20 weeks of high-fat diet (HFD) feeding, obese Ldlr-/-.Leiden mice were treated twice a week with an established anti-C5 antibody (BB5.1) or vehicle control. A separate group of mice was kept on a chow diet as a healthy reference. After 12 weeks of treatment, NASH was analyzed histopathologically, and genome-wide hepatic gene expression was analyzed by next-generation sequencing and pathway analysis. Atherosclerotic lesion area and severity were quantified histopathologically in the aortic roots. Results: Anti-C5 treatment considerably reduced complement system activity in plasma and MAC deposition in the liver but did not affect NASH. Anti-C5 did, however, reduce the development of atherosclerosis, limiting the total lesion size and severity independently of an effect on plasma cholesterol but with reductions in oxidized LDL (oxLDL) and macrophage migration inhibitory factor (MIF). Conclusion: We show, for the first time, that treatment with an anti-C5 antibody in advanced stages of NASH is not sufficient to reduce the disease, while therapeutic intervention against established atherosclerosis is beneficial to limit further progression

Evidence That Non-Syndromic Familial Tall Stature Has an Oligogenic Origin Including Ciliary Genes

Human growth is a complex trait. A considerable number of gene defects have been shown to cause short stature, but there are only few examples of genetic causes of non-syndromic tall stature. Besides rare variants with large effects and common risk alleles with small effect size, oligogenic effects may contribute to this phenotype. Exome sequencing was carried out in a tall male (height 3.5 SDS) and his parents. Filtered damaging variants with high CADD scores were validated by Sanger sequencing in the trio and three other affected and one unaffected family members. Network analysis was carried out to assess links between the candidate genes, and the transcriptome of murine growth plate was analyzed by microarray as well as RNA Seq. Heterozygous gene variants in CEP104, CROCC, NEK1, TOM1L2, and TSTD2 predicted as damaging were found to be shared between the four tall family members. Three of the five genes (CEP104, CROCC, and NEK1) belong to the ciliary gene family. All genes are expressed in mouse growth plate. Pathway and network analyses indicated close functional connections. Together, these data expand the spectrum of genes with a role in linear growth and tall stature phenotypes