Ana Barbara Garcia-Garcia

Evaluation of clinical diagnosis criteria of familial ligand defective apoB 100 and lipoprotein phenotype comparison between LDL receptor gene mutations affecting ligand-binding domain and the R3500Q mutation of the apoB gene in patients from a South European population

Familial hypercholesterolemia (FH) and familial defective apoB 100 (FDB) are characterized by increased plasma low-density lipoprotein cholesterol (LDLc) levels and risk of coronary heart disease (CHD). FDB is clinically indistinguishable from FH. The aims of this study were to evaluate clinical diagnosis criteria for FDB and to compare the lipoprotein phenotype between carriers of LDL receptor (LDLR) gene mutations that affect the ligand-binding domain and subjects with the R3500Q mutation in apoB gene. We studied 213 subjects (113 probands) with FH and 19 heterozygous FDB subjects. Genetic diagnosis was determined by following a protocol based on Southern blot and polymerase chain reaction-single strand conformation polymorphism (SSCP) analysis. Thirty FH carriers of LDLR gene missense mutations that affect ligand-binding domain were matched by age, gender, and body mass index to the 19 FDB subjects (R3500Q mutation). Lipoprotein phenotype comparison was conducted between the 2 groups. FH patients showed plasma total and LDL cholesterol levels significantly higher than those in FDB patients. Three FDB showed plasma total and LDLc values in the normal range. Using the 1999 clinical Med-Ped criteria for diagnosis of genetic hypercholesterolemia, no FDB subjects had a confirmed diagnosis; it was probable in 36% of the subjects, it was possible in 32% of the subjects, and it could be excluded in the remaining 32% of the subjects. We conclude that the FDB lipoprotein phenotype was significantly less severe than that observed in FH carriers of LDLR gene missense ligand-binding domain mutations. Clinical Med-Ped diagnosis criteria tend to under-diagnose FDB.

Influence of microsomal triglyceride transfer protein promoter polymorphism −493 Gt on fasting plasma triglyceride values and interaction with treatment response to atorvastatin in subjects with heterozygous familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is an autosomal dominant disease characterized by elevated levels of low-density lipoprotein-cholesterol (LDL-C). Phenotypic expression is highly variable, being influenced by diet, age, gender, body mass index, apolipoprotein E genotype and type of LDL-receptor gene mutation. Microsomal triglyceride (TG) transfer protein (MTP) is a protein involved in lipid metabolism. Polymorphism MTP −493 GT has been shown to modulate lipid levels in several populations. To analyse the effect of this polymorphism in the lipid phenotype expression of FH and treatment response, we studied a sample of 222 Spanish FH patients, of whom 147 were studied before and after treatment with 20 mg of atorvastatin daily during 6 weeks. The variant was analysed by polymerase chain reaction amplification and single-strand confirmation polymorphism. Treatment reduced LDL-C, total cholesterol and TGs. Baseline fasting TGs and very-low-density lipoprotein cholesterol levels were lower in female T allele carriers (TG: 111±51 mg/dl GG, 89±35 mg/dl GT, 83±26 mg/dl TT, P=0.022; very-low-density lipoprotein cholesterol: 24±13 mg/dl GG, 16±5 mg/dl GT, 17±5 mg/dl TT, P=0.018). Triglyceride response to atorvastatin was modulated by this polymorphism in men (P=0.009), but not in women, although differences between genotypes were maintained after treatment. In conclusion, the MTP −493 GT polymorphism modulates pre- and post-treatment plasma TG values of FH in Spanish subjects in a gender-specific way. Other environmental and genetic factors likely also modulate this response.

Influence of LDL receptor gene mutations and the R3500Q mutation of the apoB gene on lipoprotein phenotype of familial hypercholesterolemic patients from a South European population

Few data are available on genotype–phenotype interactions among familial hypercholesterolemia (FH) patients in South European populations and there are no data about the influence of R3500Q mutation on lipoprotein phenotype compared to low-density lipoprotein receptor (LDLR) mutations. The objective of the study is to analyze the influence of mutations in the LDLR and apolipoprotein B (apoB) genes on lipoprotein phenotype among subjects clinically diagnosed of FH living in East Spain. In all, 113 FH index patients and 100 affected relatives were studied. Genetic diagnosis was carried out following a protocol based on Southern blot and PCR-SSCP analysis. A total of 118 FH subjects could be classified into three groups according to the type of LDLR mutations (null mutations, missense mutations affecting the ligand binding 3–5 repeat, and missense mutations outside this domain). In addition, the lipoprotein phenotype of these FH groups was compared with 19 heterozygous subjects with familial ligand-defective apoB (FDB), due to R3500Q mutation. FH patients carrying missense mutations affecting the ligand binding repeat 3–5 showed total and LDL cholesterol levels significantly higher than FH patients with missense mutations in other LDLR domains or FDB patients. FH subjects carrying null mutations showed lower high-density lipoprotein cholesterol plasma values compared to FH carrying missense mutations. FDB subjects showed the lowest total and LDL cholesterol plasma values. In conclusion, the type of LDLR gene mutation and R3500Q mutation influences the lipoprotein phenotype of FH population from East Spain.

Determinantes de la lipemia posprandial medida como perfil diurno de triglicéridos en personas no diabéticas con normolipemia

BACKGROUND AND OBJECTIVE We decided to evaluate the clinical and biochemical predictors of postprandial lipemia, measured as daylong capillarly triglycerides (TGc) profiles, in normolipidemic non diabetic subjects. PATIENTS AND METHOD We studied 76 normolipidemic non diabetic subjects (45 premenopausal females). Accutrend was used to measure daylong TGc profiles during 3 days in 6 previously standardized points: fasting, pre and 3 h after dinner and lunch and at bedtime. The area under the curve of TGc (AUC-TGc) was determined as expression of postprandial lipemia. RESULTS Males showed significantly higher AUC-TGc (26.20 [11.00] vs 19.12 [6.57] in females; p < 0.001). Obese showed significantly higher values of AUC-TGc (27.87 [12.47] vs 20.05 [7.04]; p < 0.01). The AUC-TGc correlated with: age (r = 0.242; p < 0.05), body mass index (r = 0.312; p < 0.01), waist circumference (r = 0.394; p < 0.01), fasting plasma triglyceride (r = 0.634; p < 0.001), fasting insulinemia (r = 0.485; p < 0.001) and fasting HOMA (r = 0.484; p < 0.001). The multivariate analysis showed that HOMA (regression coefficient: 0.352; p = 0.02) and waist circumference (regression coefficient: 0.4; p = 0.05) were independent predictors of the AUC-TGc. CONCLUSIONS Independent determinants of postprandial lipemia were waist circumference and HOMA.

Influencia de las mutaciones HF Valencia 1 y 2 del gen del receptor de LDL sobre la respuesta terapéutica a simvastatina en sujetos con hipercolesterolemia familiar heterocigota caracterizada molecularmente

Fundamento Analizar si el diagnostico molecular de la hipercolesterolemia familiar (HF) ayuda apredecir la respuesta terapeutica a simvastatina, en una poblacion mediterranea del sur de Europa. Sujetos y metodo Hemos estudiado la respuesta terapeutica en 27 sujetos con diagnostico genetico de HF (11 varones) pertenecientes a 8 familias con HF, seleccionadas por muestreo aleatorio entre 30 familias con HF con diagnostico molecular, en un estudio de intervencion sin grupo control con 20 mg/dia de simvastatina. Comparamos las caracteristicas clinicobiologicas entre sujetos clasificados como HF mutaciones nulas ( HF Valencia 1 y Valencia 2 ; n = 11) o HF mutaciones no nulas (n = 16) en situacion basal y tras 6 semanas de tratamiento con simvastatina. Resultados Los sujetos con mutaciones nulas ( HF Valencia 1 y 2 ) que no expresan ARNmy, por tanto, no sintetizan rLDL a partir del alelo mutado, responden menos al tratamiento con simvastatina que los pacientes con HF con mutaciones no nulas. La media del porcentaje de reduccion del cLDL fue significativamente inferior en el grupo con mutaciones nulas (32,6% [9,5] frente a 42,8% [12,2], p = 0,03). Ademas, los valores plasmaticos del cHDL en situacion basal y postratamiento fueron menores en los sujetos con HF con mutaciones nulas. No encontramos diferencias estadisticamente significativas en los parametros clinicos y lipidicos en situacion basal ni tras tratamiento entre varones y mujeres. Conclusion La respuesta terapeutica a simvastatina en sujetos con HF molecularmente caracterizados es significativamente menor en los sujetos con HF con mutaciones nulas (HF Valencia1 y 2). La aplicacion de estos resultados ayudara a predecir la respuesta al tratamiento con estatinas y permitira disenar terapeuticas individualizadas en este grupo de sujetos con alto riesgo cardiovascular.

jviz webcomponents: a foundation js framework for clinical NGS bioinformatics

IntroductionMGviz is a fully integrated NGS QC and data analisis suite that creates automatic NGS clinical reports for clinicians to review. Summarized quality control measures with threshold based from all the previous runs are computed to warm about any kind of bias and check also for sample swap. These are Intuitive and interactive tools that help prioritize and select the variants of interest related to the patients phenotype from our NGS gene panels and commercial exome panels.Materials and Methods: We have created javascript webcomponents that can be easily integrated in web applications. Each component has his own API reference described in the jviz GitHub.These components can import the data from an associated RESTful service, and achieve great interactivity by means of the use of HTML5 canvas element as a drawing mechanism. Results: A suite of independent webcomponents, that intercommunicate via events give them great modularity and strength. Also, it allows the easy integration of several of them in fully functional web applications for quality control of the NGS analysis and the variants prioritization for the genetic diagnosis. Conclusions:We have also developed a full suit of open source tools in python, R and MEAN stack for creating clinical bioinformatics as a service. All this is bases in our own modern js library for interactive bioinformatic visualization: jviz (https://github.com/jviz). This study an JMJ has been funded by Instituto de Salud Carlos III “IFI15/00138” (Co-funded by European Regional Development Fund/European Social Fund).