👤 Andraž Petek

Thyroid hormones regulate lipoprotein metabolism-primarily by up-regulating the LDL receptor. Whether TSH relates to LDL-C in hypercholesterolemic children, and whether this depends on familial hypercholesterolemia (FH) status or the underlying defective gene, is uncertain. We evaluated TSH-lipid associations in prepubertal children and tested effect modification by FH status and, within FH, by gene with a pathogenic variant (LDLR vs APOB). We performed a cross-sectional study of prepubertal children referred to the Slovenian national tertiary center through the universal FH screening program or cascade screening. Eligibility required concurrent TSH and fasting lipid measurement and completed genetic testing (pathogenic/likely pathogenic variants in LDLR/APOB/PCSK9 vs polygenic hypercholesterolemia). Among 738 children, 182 (24.7%) were FH-positive (LDLR 132; APOB 50). In the pooled cohort, TSH did not correlate with age or lipids (all p ≥ 0.050). After sex stratification, TSH correlated with triglycerides only in males (ρ = 0.156; p = 0.012). In FH-positive children, TSH correlated with total cholesterol, LDL-cholesterol, and ApoB (ρ ~ 0.184-0.207; all p < 0.050), with no associations in FH-negative children. Interaction testing confirmed effect modification by FH (TSH × FH β = 0.141 mmol/L per mIU/L, p = 0.023). Within FH-positive children, a positive TSH-LDL-C slope was seen in LDLR carriers (β = 0.237, p = 0.004) but not in APOB carriers (β = -0.065, p = 0.655). TSH was positively associated with LDL-C only in FH due to LDLR variants, not in APOB carriers. These findings suggest that genetic background may shape hormonal sensitivity, and that attention to thyroid status could be particularly relevant in LDLR-FH. Show less

Autism or autism spectrum disorder (ASD) is a range of neurodevelopmental disorders starting in early childhood and is characterized by impairments in communication and reciprocal social interaction and presence of restricted and repetitive patterns of behavior. The contribution of genetic factors to autism is clear in twin and family studies. It is apparent that, overall, ASD is a complex non-Mendelian disorder. Recent studies suggest that copy number variations (CNVs) play a significant role in the etiology of ASD. For the current work, we recruited 245 family members from 73 ASD families from Styria, Austria. The DNA from probands was genotyped with Affymetrix single nucleotide polymorphism (SNP) 6.0 microarrays to screen for CNVs in their genomes. Analysis of the microarray data was performed using three different algorithms, and a list of stringent calls was compared to existing CNV data from over 2,357 controls of European ancestry. For stringent calls not present in controls, quantitative real-time PCR (qRT-PCR) was used to validate the CNVs in the probands and in their family members. Twenty-two CNVs were validated from this set (five of which are apparently de novo), many of which appear likely to disrupt genes that may be considered as good candidates for neuropsychiatric disorders, including DLG2, S100B, ARX, DIP2A, HPCAL1, and GPHN. Several others disrupt genes that have previously been implicated in autism, such as BDNF, AUTS2, DPP6, and C18orf22, and our data add to the growing evidence of their involvement in ASD. Show less

The GPHN gene codes for gephyrin, a key scaffolding protein in the neuronal postsynaptic membrane, responsible for the clustering and localization of glycine and GABA receptors at inhibitory synapses. Gephyrin has well-established functional links with several synaptic proteins that have been implicated in genetic risk for neurodevelopmental disorders such as autism spectrum disorder (ASD), schizophrenia and epilepsy including the neuroligins (NLGN2, NLGN4), the neurexins (NRXN1, NRXN2, NRXN3) and collybistin (ARHGEF9). Moreover, temporal lobe epilepsy has been linked to abnormally spliced GPHN mRNA lacking exons encoding the G-domain of the gephyrin protein, potentially arising due to cellular stress associated with epileptogenesis such as temperature and alkalosis. Here, we present clinical and genomic characterization of six unrelated subjects, with a range of neurodevelopmental diagnoses including ASD, schizophrenia or seizures, who possess rare de novo or inherited hemizygous microdeletions overlapping exons of GPHN at chromosome 14q23.3. The region of common overlap across the deletions encompasses exons 3-5, corresponding to the G-domain of the gephyrin protein. These findings, together with previous reports of homozygous GPHN mutations in connection with autosomal recessive molybdenum cofactor deficiency, will aid in clinical genetic interpretation of the GPHN mutation spectrum. Our data also add to the accumulating evidence implicating neuronal synaptic gene products as key molecular factors underlying the etiologies of a diverse range of neurodevelopmental conditions. Show less