👤 Angela Del Pozo

Next generation sequencing (NGS) has expanded the diagnostic paradigm turning the focus to the growth plate. The aim of the study was to determine the prevalence of variants in genes implicated in skeletal dysplasias in probands with short stature and mild skeletal anomalies. Clinical and radiological data were collected from 108 probands with short stature and mild skeletal anomalies. A customized skeletal dysplasia NGS panel was performed. Variants were classified using ACMG recommendations and Sherloc. Anthropometric measurements and skeletal anomalies were subsequently compared in those with or without an identified genetic defect. Heterozygous variants were identified in 21/108 probands (19.4%). Variants were most frequently identified in ACAN (n = 10) and IHH (n = 7) whilst one variant was detected in COL2A1, CREBBP, EXT1, and PTPN11. Statistically significant differences (P < 0.05) were observed for sitting height/height (SH/H) ratio, SH/H ratio standard deviation score (SDS), and the SH/H ratio SDS >1 in those with an identified variant compared to those without. A molecular defect was elucidated in a fifth of patients. Thus, the prevalence of mild forms of skeletal dysplasias is relatively high in individuals with short stature and mild skeletal anomalies, with variants in ACAN and IHH accounting for 81% of the cases. An elevated SH/H ratio appears to be associated with a greater probability in detecting a variant, but no other clinical or radiological feature has been found determinant to finding a genetic cause. Currently, we cannot perform extensive molecular studies in all short stature individuals so detailed clinical and radiological phenotyping may orientate which are the candidate patients to obtain worthwhile results. In addition, detailed phenotyping of probands and family members will often aid variant classification. Show less

ChREBP is an essential transcription factor for lipogenesis. Its physiological role in adipose tissue has been studied only to a small extent and the control of its expression remains unknown in human adipocytes. We have studied ChREBP mRNA and protein expression levels in the liver and the omental (OM) and subcutaneous (SC) adipose tissues from obese and lean subjects, as well as in human differentiated preadipocytes. Liver and OM and SC adipose tissue biopsies were obtained from lean and obese patients. Human preadipocytes were isolated from the adipose tissues from obese patients and differentiated under adipogenic conditions. ChREBP expression levels were quantified by RT-PCR and Western blot analysis. We found opposing results in terms of ChREBP regulation in the liver and adipose samples. ChREBP increased in the liver from obese compared to lean subjects, whereas the expression decreased in both adipose tissues. The mRNAs of other adipogenic markers were checked in these tissues. The pattern of FASN was similar to the one for ChREBP, ADCY3 decreased in both adipose tissues from obese patients, AP2 decreased only in OM adipose tissue of obese patients and ATGL did not change. The levels of ChREBP mRNA and protein showed dramatic increases during the differentiation of human OM and SC preadipocytes. In conclusion, ChREBP expression has an opposite regulation in the liver and adipose tissue from obese subjects which is compatible with the increased hepatic lipogenesis and decreased adipocytic lipogenesis found in these patients. The dramatic increase of ChREBP mRNA and protein levels during preadipocyte differentiation suggests a role in adipogenesis. Show less