👤 Francisco M De La Vega

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder characterized by severe hypertriglyceridemia and caused by mutations in genes involved in chylomicron metabolism. Dietary management includes a very-low-fat diet, restriction of simple carbohydrates and alcohol, supplementation with medium-chain triglycerides, essential fatty acids, and fat-soluble vitamins; however, long-term adherence is often poor and nutritional therapy alone is insufficient. We report two adult Chilean sisters with FCS caused by the homozygous Q97X mutation in the APOA5 gene. Both patients experienced severe hypertriglyceridemia (>5,000 mg/dL) and recurrent episodes of acute pancreatitis. One sister was treated with volanesorsen, an antisense oligonucleotide, receiving a weekly dose of 285 mg, which was repeated every 3 weeks due to thrombocytopenia. When combined with structured nutritional counseling, pharmacological treatment achieved a marked reduction in plasma triglycerides to <250 mg/dL and a substantial improvement in quality of life. The other sister was managed with conventional therapy due to a lack of health insurance coverage for volanesorsen. She presented persistent hypertriglyceridemia and recurrent hospitalizations, underscoring the challenges of access to advanced therapies in limited-resource settings. While volanesorsen offers a promising therapeutic alternative, equitable access remains a critical issue, particularly in health systems of low-to middle-income regions. Show less

Familial hypercholesterolemia (FH) is a genetic disorder driven in part by mutations in three genes that encode components of the cholesterol pathway: LDLR, APOB, and PCSK9. However, the majority of FH genetics has been performed in individuals of European descent. Here, we leveraged a cohort of 300 patients from the Mexican FH registry to understand how rare, high liability alleles and common variants might contribute to shaping individual risk. Using a combination of whole exome and of short- and long-read whole genome sequencing, we report three key findings. First, we observed that rare pathogenic point mutations and structural variants in all known FH genes, together with variants in APOE, CREB3L3, and PLIN1, contribute to a molecular FH diagnosis in 67% of families, including novel gene-disruptive copy number variants (CNVs) which arose in a native American background. Second, ancestry-adjusted polygenic risk score analysis identified a significant liability for coronary artery disease, hypertension, LDL, HDL, and Type 2 Diabetes. The polygenic signal for LDL was present in patients with rare, pathogenic FH mutations and was more prominent in individuals bereft of a molecular FH diagnosis. Finally, we report both a whole-gene duplication and common, non-coding variants in a novel locus, PDZK1, which contribute to the genetic burden of FH, a finding we replicated in the UK Biobank (UKB). Together, our analyses illustrate the value of genetic studies in non-European populations and reinforce the notion that individual risk to disease can arise from both rare, large effect alleles (alone or in combination across genes) and common variants that increase the mutational burden of a biological system. Show less

Analyze the molecular mimicry between Plasmodium spp. and autoantigens associated with GBS, identifying possible antigenic epitopes. PSI-Blast, Praline, Emboss, Protein Data Bank, Swiss Model Server, AlphaFold 2, Ellipro and PyMol 2.3 were used to search for homologies, perform alignments, obtain protein structures, and predict epitopes. 17 autoantigens and seven immunological targets of the peripheral nervous system were included, identifying 72 possible epitopes associated with GBS. From the proteome of Plasmodium spp. (298 proteins), only two showed similarities close to 30% with TRIM21 and BACE1, generating seven possible epitopes. No significant homologies were observed between the proteome of GBS and Plasmodium spp. The exploration of other mechanisms such as immune-mediated capillary damage, Epitope Spreading or Bystander Activation is suggested to explain the mentioned association. These findings underscore the need to clarify the etiology of autoimmune diseases and the role of pathogens. The need for experimental studies to validate these results is emphasized. Show less

Urea cycle disorders (UCD) are inborn errors of metabolism caused by deficiency of enzymes required to convert nitrogen from ammonia into urea. Current paradigms of treatment focus on dietary manipulations, ammonia scavenger drugs, and liver transplantation. The aim of this study was to describe the characteristics and indication of liver transplantation in UCD in a tertiary hospital. We performed a retrospective study of children with UCD seen in the period 2000-2021. Data was collected on clinical onset, hyperammonemia severity, evolution and liver transplantation. There were 33 patients in the study period, whose diagnosis were: ornithine transcarbamylase (OTC, Show less

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

Gestational diabetes (GD) alters normal fetal development and is related to a diabetogenic effect in the progeny. Liver X receptors (LXRs) are considered to be potential drug targets for the regulation, treatment, or prevention of diabetes. The aim of this study was to evaluate early and late changes of LXR in the hippocampus and hypothalamus of the male and female offspring of control (CO) and diabetic (DO) mothers. We used an experimental model of streptozotocin-induced GD to assess the protein expression of LXRα (NR1H3) and LXRβ (NR1H2) by western blotting. The tissues were obtained from CO and DO animals at postnatal day 1 (1D), day 10 (10D), and day 35 (35D) and 9 months (9M). In CO, the LXR expression showed significant differences among the groups, which were tissue- and receptor-specific (P<0.05). Sex differences in CO were found only in the hypothalamus for LXRβ expression at 35D and 9M (P<0.05). When CO and DO were compared, differences between them were observed in the majority of the studied groups at 1D (male hippocampus, LXRα 31% and LXRβ 161%; female hippocampus, LXRβ 165%; male hypothalamus, LXRβ 182%; and female hypothalamus, LXRα 85%; P<0.05). However, these differences disappeared later with the exception of LXRβ expression in the male hypothalamus (P<0.05). The area under the curve during the glucose tolerance test correlated negatively with LXRβ in CO but not in DO animals. Moreover, in a male DO subpopulation this correlation was positive as it occurs in intolerant animals. These results indicate that GD affects hypothalamic LXR expression differently in male and female offspring. Show less

Liver X receptor (LXR) α and β are nuclear receptors that are crucial for the regulation of carbohydrate and lipid metabolism. Activation of LXRs in the brain facilitates cholesterol clearance and improves cognitive deficits, thus they are considered as promising drug targets to treat diseases such as atherosclerosis and Alzheimer's disease. Nevertheless, little is known about the function and localization of LXRs in the brain. Here, we studied the expression of LXR in the brains of rats that received free access to 10% (w/v) fructose group (FG) in their beverages or water control drinks (control group (CG)). After 6 weeks rats in the FG presented with hypertriglyceridemia, hyperinsulinemia, and became glucose intolerant, suggesting a progression toward type 2 diabetes. We found that hypothalamic LXR expression was altered in fructose-fed rats. Rats in the FG presented with a decrease in LXRβ levels while showing an increase in LXRα expression in the hypothalamus but not in the hippocampus, cerebellum, or neocortex. Moreover, both LXRα and β expression correlated negatively with insulin and triglyceride levels. Interestingly, LXRβ showed a negative correlation with the area under the curve during the glucose tolerance test in the CG and a positive correlation in the FG. Immunocytochemistry revealed that the paraventricular and ventromedial nuclei express mainly LXRα whereas the arcuate nucleus expresses LXRβ. Both LXR immunosignals were found in the median preoptic area. This is the first study showing a relationship between glucose and lipid homeostasis and the expression of LXRs in the hypothalamus, suggesting that LXRs may trigger neurochemical and neurophysiological responses for the control of food intake and energy expenditure through these receptors. Show less

The genetics and linkage relationships of several isozymatic and morphological markers have been investigated in different cultivars of rye (Secale cereale L.). The inheritance and the variability among cultivars of three new isozymatic zones are described: GOT2 and LAP, each of them under the control of a two-allele single locus, namely Got2 and Lap, respectively; and 6PGD1 controlled by two loci, 6Pgd1a and 6Pgd1b, which have alleles in common. Four linkage groups have been found: Acp2-Acp3, Got3-Mdh2-Lper4, Mdh1-6Pgd2-Pgi2, and Pgm-Eper2-[Eper1-Eper3]. The assignment of these four groups to the chromosomes 7R, 3R, 1R, and 4R is discussed. Show less