Unraveling the genetic background of individuals with a clinical familial hypercholesterolemia phenotype

Familial hypercholesterolemia (FH) is a common genetic disorder of lipid metabolism caused by pathogenic/likely pathogenic variants in LDLR, APOB, and PCSK9 genes. Variants in FH-phenocopy genes (LDLRAP1, APOE, LIPA, ABCG5, and ABCG8), polygenic hypercholesterolemia, and hyperlipoprotein (a) [Lp(a)] can also mimic a clinical FH phenotype. We aim to present a new diagnostic tool to unravel the genetic background of clinical FH phenotype. Biochemical and genetic study was performed in 1,005 individuals with clinical diagnosis of FH, referred to the Portuguese FH Study. A next-generation sequencing panel, covering eight genes and eight SNPs to determine LDL-C polygenic risk score and LPA genetic score, was validated, and used in this study. FH was genetically confirmed in 417 index cases: 408 heterozygotes and 9 homozygotes. Cascade screening increased the identification to 1,000 FH individuals, including 11 homozygotes. FH-negative individuals (phenotype positive and genotype negative) have Lp(a) >50 mg/dl (30%), high polygenic risk score (16%), other monogenic lipid metabolism disorders (1%), and heterozygous pathogenic variants in FH-phenocopy genes (2%). Heterozygous variants of uncertain significance were identified in primary genes (12%) and phenocopy genes (7%). Overall, 42% of our cohort was genetically confirmed with FH. In the remaining individuals, other causes for high LDL-C were identified in 68%. Hyper-Lp(a) or polygenic hypercholesterolemia may be the cause of the clinical FH phenotype in almost half of FH-negative individuals. A small part has pathogenic variants in ABCG5/ABCG8 in heterozygosity that can cause hypercholesterolemia and should be further investigated. This extended next-generation sequencing panel identifies individuals with FH and FH-phenocopies, allowing to personalize each person's treatment according to the affected pathway.

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

BACKGROUND

Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies.

METHODS

For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia.

FINDINGS

Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified.

INTERPRETATION

Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life.

FUNDING

Pfizer, Amgen, Merck Sharp & Dohme, Sanofi-Aventis, Daiichi Sankyo, and Regeneron.

Generation and validation of a classification model to diagnose familial hypercholesterolaemia in adults

BACKGROUND AND AIMS

The early diagnosis of familial hypercholesterolaemia is associated with a significant reduction in cardiovascular disease (CVD) risk. While the recent use of statistical and machine learning algorithms has shown promising results in comparison with traditional clinical criteria, when applied to screening of potential FH cases in large cohorts, most studies in this field are developed using a single cohort of patients, which may hamper the application of such algorithms to other populations. In the current study, a logistic regression (LR) based algorithm was developed combining observations from three different national FH cohorts, from Portugal, Brazil and Sweden. Independent samples from these cohorts were then used to test the model, as well as an external dataset from Italy.

METHODS

The area under the receiver operating characteristics (AUROC) and precision-recall (AUPRC) curves was used to assess the discriminatory ability among the different samples. Comparisons between the LR model and Dutch Lipid Clinic Network (DLCN) clinical criteria were performed by means of McNemar tests, and by the calculation of several operating characteristics.

RESULTS

AUROC and AUPRC values were generally higher for all testing sets when compared to the training set. Compared with DLCN criteria, a significantly higher number of correctly classified observations were identified for the Brazilian (p < 0.01), Swedish (p < 0.01), and Italian testing sets (p < 0.01). Higher accuracy (Acc), G mean and F1 score values were also observed for all testing sets.

CONCLUSIONS

Compared to DLCN criteria, the LR model revealed improved ability to correctly classify observations, and was able to retain a similar number of FH cases, with less false positive retention. Generalization of the LR model was very good across all testing samples, suggesting it can be an effective screening tool if applied to different populations.

Genetic Testing in Familial Hypercholesterolemia: Is It for Everyone?

PURPOSE OF REVIEW

Lipid measurements and genetic testing are the main diagnostic tools for FH screening that are available in many countries. A lipid profile is widely accessible, and genetic testing, although available worldwide, in some countries is only performed in a research context. Still FH is diagnosed late, showing lack of early screening programs worldwide.

RECENT FINDINGS

Pediatric screening of FH was recently recognized by the European Commission Public Health Best Practice Portal as one on the best practices in non-communicable disease prevention. The early diagnosis of FH and the lowering of LDL-C values over lifespan can reduce the risk of coronary artery disease and offer health and socioeconomic gains. Current knowledge about FH shows that early detection through appropriate screening needs to become a priority in healthcare systems worldwide. Governmental programs for FH identification should be implemented to unify the diagnosis and increase patient identification.

Sexual dimorphism in Kinosternon scorpioides (Linnaeus, 1766) from the Brazilian Amazon

The sexual dimorphism of the Kinosternon scorpioides was evaluated using two different techniques (linear and geometric morphometry) from images and linear measurements of the carapace and plastron of adults (male and female). Linear morphometry indicated that the height and width of carapace and plastron are statistically different between sexes, with females being wider and taller. In the evaluation of geometric morphometry, ANOVA demonstrated variation in the size of the plastron and the shape of the carapace and plastron, expressing a tendency in shape for each sex. Sexual dimorphism, therefore, is verified for this species, notably by the plastron. This study indicates an additional tool for the phenotypic knowledge of animals, contributing to the study of threatened populations.

Comparative study on the performance of different classification algorithms, combined with pre- and post-processing techniques to handle imbalanced data, in the diagnosis of adult patients with familial hypercholesterolemia

Familial Hypercholesterolemia (FH) is an inherited disorder of cholesterol metabolism. Current criteria for FH diagnosis, like Simon Broome (SB) criteria, lead to high false positive rates. The aim of this work was to explore alternative classification procedures for FH diagnosis, based on different biological and biochemical indicators. For this purpose, logistic regression (LR), naive Bayes classifier (NB), random forest (RF) and extreme gradient boosting (XGB) algorithms were combined with Synthetic Minority Oversampling Technique (SMOTE), or threshold adjustment by maximizing Youden index (YI), and compared. Data was tested through a 10 × 10 repeated k-fold cross validation design. The LR model presented an overall better performance, as assessed by the areas under the receiver operating characteristics (AUROC) and precision-recall (AUPRC) curves, and several operating characteristics (OC), regardless of the strategy to cope with class imbalance. When adopting either data processing technique, significantly higher accuracy (Acc), G-mean and F₁ score values were found for all classification algorithms, compared to SB criteria (p < 0.01), revealing a more balanced predictive ability for both classes, and higher effectiveness in classifying FH patients. Adjustment of the cut-off values through pre or post-processing methods revealed a considerable gain in sensitivity (Sens) values (p < 0.01). Although the performance of pre and post-processing strategies was similar, SMOTE does not cause model’s parameters to loose interpretability. These results suggest a LR model combined with SMOTE can be an optimal approach to be used as a widespread screening tool.

Performance comparison of different classification algorithms applied to the diagnosis of familial hypercholesterolemia in paediatric subjects

Familial Hypercholesterolemia (FH) is an inherited disorder of lipid metabolism, characterized by increased low density lipoprotein cholesterol (LDLc) levels. The main purpose of the current work was to explore alternative classification methods to traditional clinical criteria for FH diagnosis, based on several biochemical and biological indicators. Logistic regression (LR), decision tree (DT), random forest (RF) and naive Bayes (NB) algorithms were developed for this purpose, and thresholds were optimized by maximization of Youden index (YI). All models presented similar accuracy (Acc), specificity (Spec) and positive predictive values (PPV). Sensitivity (Sens) and G-mean values were significantly higher in LR and RF models, compared to the DT. When compared to Simon Broome (SB) biochemical criteria for FH diagnosis, all models presented significantly higher Acc, Spec and G-mean values (p < 0.01), and lower negative predictive value (NPV, p < 0.05). Moreover, LR and RF models presented comparable Sens values. Adjustment of the cut-off point by maximizing YI significantly increased Sens values, with no significant loss in Acc. The obtained results suggest such classification algorithms can be a viable alternative to be used as a widespread screening method. An online application has been developed to assess the performance of the LR model in a wider population.

Polygenic contribution for familial hypercholesterolemia (FH)

PURPOSE OF REVIEW

The present review summarizes different polygenic risk scores associated with hypercholesterolemia applied to cohorts with a genetic diagnosis of familial hypercholesterolemia (FH).

RECENT FINDINGS

Several single-nucleotide polymorphisms associated with increased levels of LDL-C or Lp(a) have been genotyped in population cohorts with FH phenotype, to identify the cause of hypercholesterolemia in mutation negative individuals. In different studies, a large proportion of individuals without a monogenic causative variant (in low density lipoprotein receptor gene (LDLR), apolipoprotein B gene (APOB) or proprotein convertase subtilisin/kexin type 9 gene (PCSK9 genes) was considered to have a hypercholesterolemia with a polygenic basis. The heterogeneity in the phenotype of monogenic FH may also be explained by polygenic contributions to LDL-C. The elevated LDL-C genetic risk score (GRS) has been associated with increased risk of atherosclerotic cardiovascular disease in individuals with monogenic FH. Moreover, a poorer response to lipid lowering therapy has been associated with monogenic FH when compared to a polygenic basis. The reason why Lp(a) concentrations are raised in individuals with clinical FH is unclear, but it could be caused by a genetic variation in Lipoprotein(A) gene as a polygenic contribution.

SUMMARY

Polygenic risk scores have revealed to be important tools to define the cause of hypercholesterolemia in FH mutation-negative individuals and should be included in FH diagnosis strategies, although there is still space for more specific LDL-C GRS to be developed. The use of GRS may be used to refine cardiovascular risk prediction in FH patients and could lead to a personalized approach to therapy. The identification of the genetic status of an individual with FH phenotype (monogenic or polygenic) may have implications on their risk stratification, cascade screening of relatives, disease management and therapeutic measures.

The familial hypercholesterolaemia phenotype: Monogenic familial hypercholesterolaemia, polygenic hypercholesterolaemia and other causes

Familial hypercholesterolaemia (FH) is a monogenic disorder characterised by high low-density lipoprotein cholesterol (LDL-C) concentrations and increased cardiovascular risk. However, in clinically defined FH cohorts worldwide, an FH-causing variant is only found in 40%-50% of the cases. The aim of this work was to characterise the genetic cause of the FH phenotype in Portuguese clinical FH patients. Between 1999 and 2017, 731 index patients (311 children and 420 adults) who met the Simon Broome diagnostic criteria had been referred to our laboratory. LDLR, APOB, PCSK9, APOE, LIPA, LDLRAP1, ABCG5/8 genes were analysed by polymerase chain reaction amplification and Sanger sequencing. The 6-SNP LDL-C genetic risk score (GRS) for polygenic hypercholesterolaemia was validated in the Portuguese population and cases with a GRS over the 25th percentile were considered to have a high likelihood of polygenic hypercholesterolaemia. An FH-causing mutation was found in 39% of patients (94% in LDLR, 5% APOB and 1% PCSK9), while at least 29% have polygenic hypercholesterolaemia and 1% have other lipid disorders. A genetic cause for the FH phenotype was found in 503 patients (69%). All known causes of the FH phenotype should be investigated in FH cohorts to ensure accurate diagnosis and appropriate management.

Phenotypical, Clinical, and Molecular Aspects of Adults and Children With Homozygous Familial Hypercholesterolemia in Iberoamerica

OBJECTIVE

Characterize homozygous familial hypercholesterolemia (HoFH) individuals from Iberoamerica. Approach and Results: In a cross-sectional retrospective evaluation 134 individuals with a HoFH phenotype, 71 adults (age 39.3±15.8 years, 38.0% males), and 63 children (age 8.8±4.0 years, 50.8% males) were studied. Genetic characterization was available in 129 (96%). The majority (91%) were true homozygotes (true HoFH, n=79, 43.0% children, 46.8% males) or compound heterozygotes (compound heterozygous familial hypercholesterolemia, n=39, 51.3% children, 46.2% males) with putative pathogenic variants in the LDLR. True HoFH due to LDLR variants had higher total (P=0.015) and LDL (low-density lipoprotein)-cholesterol (P=0.008) compared with compound heterozygous familial hypercholesterolemia. Children with true HoFH (n=34) tended to be diagnosed earlier (P=0.051) and had a greater frequency of xanthomas (P=0.016) than those with compound heterozygous familial hypercholesterolemia (n=20). Previous major cardiovascular events were present in 25 (48%) of 52 children (missing information in 2 cases), and in 43 (67%) of 64 adults with LDLR variants. Children who are true HoFH had higher frequency of major cardiovascular events (P=0.02), coronary heart (P=0.013), and aortic/supra-aortic valve diseases (P=0.022) than compound heterozygous familial hypercholesterolemia. In adults, no differences were observed in major cardiovascular events according to type of LDLR variant. From 118 subjects with LDLR variants, 76 (64%) had 2 likely pathogenic or pathogenic variants. In 89 subjects with 2 LDLR variants, those with at least one null allele were younger (P=0.003) and had a greater frequency of major cardiovascular events (P=0.038) occurring at an earlier age (P=0.001).

CONCLUSIONS

There was a high frequency of cardiovascular disease even in children. Phenotype and cardiovascular complications were heterogeneous and associated with the type of molecular defect.

Analysis of publicly available LDLR, APOB, and PCSK9 variants associated with familial hypercholesterolemia: application of ACMG guidelines and implications for familial hypercholesterolemia diagnosis

PurposeFamilial hypercholesterolemia (FH) is an autosomal disorder of lipid metabolism presenting with increased cardiovascular risk. Although more than 1,700 variants have been associated with FH, the great majority have not been functionally proved to affect the low-density lipoprotein receptor cycle. We aimed to classify all described variants associated with FH and to establish the proportion of variants that lack evidence to support their pathogenicity.MethodsWe followed American College of Medical Genetics and Genomics (ACMG) guidelines for the classification, and collected information from a variety of databases and individual reports. A worldwide overview of publicly available FH variants was also performed.ResultsA total of 2,104 unique variants were identified as being associated with FH, but only 166 variants have been proven by complete in vitro functional studies to be causative of disease. Additionally, applying the ACMG guidelines, 1,097 variants were considered pathogenic or likely pathogenic. Only seven variants were found in all five continents.ConclusionThe lack of functional evidence for about 85% of all variants found in FH patients can compromise FH diagnosis and patient prognosis. ACMG classification improves variant interpretation, but functional studies are necessary to understand the effect of about 40% of all variants reported. Nevertheless, ACMG guidelines need to be adapted to FH for a better diagnosis.

Genotype x environment interaction on experimental hybrids of chili pepper

In Brazil, cultivation of hybrid plants comprise near 40% of the area grown with vegetables. For Capsicum, hybrids of bell and chili peppers have already exceeded 50% and over 25% of all are commercialized seeds. This study aimed to evaluate new pepper hybrids in two environments, Cáceres, MT, and Campos dos Goytacazes, RJ, Brazil. Nine experimental hybrids of C. baccatum var. pendulum were tested and trials were performed in a randomized block design, with three replications and eight plants per plot. In each environment, plants were assessed for canopy diameter, plant height, number of fruit per plant, mean fruit mass per plant, fruit length and diameter, pulp thickness, and content of soluble solids. Seven of the eight traits have differed significantly due to environment variation. Furthermore, genotype and environment interaction was highly significant for number of fruit per plant, mean fruit mass per plant, fruit length, and fruit diameter. Choosing a hybrid to be grown in one of the studied locations must be in accordance with the sought characteristics since there is a complex interaction for some studied traits.

Lysosomal acid lipase deficiency: A hidden disease among cohorts of familial hypercholesterolemia?

BACKGROUND

Lysosomal acid lipase deficiency (LALD) is an autosomal recessive disorder and an unrecognized cause of dyslipidemia. Patients usually present with dyslipidemia and altered liver function and mutations in LIPA gene are the underlying cause of LALD.

OBJECTIVE

The aim of this study was to investigate LALD in individuals with severe dyslipidemia and/or liver steatosis.

METHODS

Coding, splice regions, and promoter region of LIPA were sequenced by Sanger sequencing in a cohort of mutation-negative familial hypercholesterolemia (FH) patients (n = 492) and in a population sample comprising individuals with several types of dyslipidemia and/or liver steatosis (n = 258).

RESULTS

This study led to the identification of LALD in 4 children referred to the Portuguese FH Study, all with a clinical diagnosis of FH. Mild liver dysfunction was present at the age of FH diagnosis; however, a diagnosis of LALD was not considered. No adults at the time of referral have been identified with LALD.

CONCLUSION

LALD is a life-threatening disorder, and early identification is crucial for the implementation of specific treatment to avoid premature mortality. FH cohorts should be investigated to identify possible LALD patients, who will need appropriate treatment. These results highlight the importance of correctly identifying the etiology of the dyslipidemia.

Molecular and agronomic analysis of intraspecific variability in Capsicum baccatum var. pendulum accessions

Capsicum baccatum is one of the most important chili peppers in South America, since this region is considered to be the center of origin and diversity of this species. In Brazil, C. baccatum has been widely explored by family farmers and there are different local names for each fruit phenotype, such as cambuci and dedo-de-moça (lady's finger). Although very popular among farmers and consumers, C. baccatum has been less extensively studied than other Capsicum species. This study describes the phenotypic and genotypic variability in C. baccatum var. pendulum accessions. Twenty-nine accessions from the Universidade Estadual do Norte Fluminense Darcy Ribeiro gene bank, and one commercial genotype ('BRS-Mari') were evaluated for 53 morphoagronomic descriptors (31 qualitative and 22 quantitative traits). In addition, accessions were genotyped using 30 microsatellite primers. Three accessions from the C. annuum complex were included in the molecular characterization. Nine of 31 qualitative descriptors were monomorphic, while all quantitative descriptors were highly significant different between accessions (P < 0.01). Using the unweighted pair group method using arithmetic averages, four groups were obtained based on multicategoric variables and five groups were obtained based on quantitative variables. In the genotyping analysis, 12 polymorphic simple sequence repeat primers amplified in C. baccatum with dissimilarity between accessions ranging from 0.13 to 0.91, permitting the formation of two distinct groups for Bayesian analysis. These results indicate wide variability among the accessions comparing phenotypic and genotypic data and revealed distinct patterns of dissimilarity between matrices, indicating that both steps are valuable for the characterization of C. baccatum var. pendulum accessions.

Occurrence and use of an estuarine habitat by giant manta ray Manta birostris

Based on the knowledge of local artisanal fishermen and on direct observations, this study presents evidence that the giant manta ray Manta birostris uses the Paranaguá estuarine complex in south Brazil, south-western Atlantic Ocean, in a predictable seasonal pattern. Behavioural observations suggest that the estuary can act as a nursery ground for M. birostris during the summer.

Familial hypercholesterolemia: Molecular characterization of possible cases from the Azores Islands (Portugal)

Familial hypercholesterolemia (FH) is an autosomal dominant disorder of the cholesterol metabolism, which constitutes a risk factor for coronary arterial disease (CAD). In the Azores Islands (Portugal), where mortality from CAD doubles its rate comparatively to the rest of the country and where a high frequency of dyslipidemia has been reported, the prevalence and distribution of FH remain unknown. The molecular characterization of a group of 33 possible cases of FH of Azorean background was undertaken in this study. A DNA array was initially used to search mutations in the LDLR, APOB and PCSK9 loci in 10 unrelated possible cases of FH. No mutations were detected in the array; after sequencing the full LDLR gene, 18 variants were identified, corresponding to two missense (c.806G > A; c.1171G > A) and sixteen synonymous alterations. Six of the synonymous variants which are consistently described in the literature as associated with altered cholesterol levels were used to build haplotypes. The most frequent haplotype corresponded to TTCGCC (45%), a “risk” haplotype, formed exclusively by alleles that were reported to increase cholesterol levels. Some of the variants detected in the full sequencing of the LDLR gene fell within the ligand-binding domain of this gene, defined by exons 2 to 6. To add information as to the role of such variants, these exons were sequenced in the remaining 23 possible FH cases. Two missense alterations (c.185C > T; c.806G > A) were found in this subset of possible FH cases. The missense alteration c.185C > T, identified in one individual, is novel for the Portuguese population. In silico analysis was not conclusive for this alteration, whose role will have to be further investigated. This study represents the first approach to the establishment of the mutational profile of FH in the Azores Islands.

Cardiovascular risk assessment of dyslipidemic children: analysis of biomarkers to identify monogenic dyslipidemia

The distinction between a monogenic dyslipidemia and a polygenic/environmental dyslipidemia is important for the cardiovascular risk assessment, counseling, and treatment of these patients. The present work aims to perform the cardiovascular risk assessment of dyslipidemic children to identify useful biomarkers for clinical criteria improvement in clinical settings. Main cardiovascular risk factors were analyzed in a cohort of 237 unrelated children with clinical diagnosis of familial hypercholesterolemia (FH). About 40% carried at least two cardiovascular risk factors and 37.6% had FH, presenting mutations in LDLR and APOB. FH children showed significant elevated atherogenic markers and lower concentration of antiatherogenic particles. Children without a molecular diagnosis of FH had higher levels of TGs, apoC2, apoC3, and higher frequency of BMI and overweight/obesity, suggesting that environmental factors can be the underlying cause of their hypercholesterolem≥ia. An apoB/apoA1 ratio ≥0.68 was identified as the best biomarker (area under the curve = 0.835) to differentiate FH from other dyslipidemias. The inclusion in clinical criteria of a higher cut-off point for LDL cholesterol or an apoB/apoA1 ratio ≥0.68 optimized the criteria sensitivity and specificity. The correct identification, at an early age, of all children at-risk is of great importance so that specific interventions can be implemented. apoB/apoA1 can improve the identification of FH patients.

Genetic divergence among African cowpea lines based on morphoagronomic traits

The aim of this study was to estimate the genetic divergence between African cowpea lines from the Cowpea Germplasm Bank of Embrapa Meio-Norte, Brazil. The morphoagronomic diversity of 57 cowpea lines was assessed using multivariate analysis. The germplasm was evaluated in August 2009 using a randomized block design with three replications based on the following traits: number of pods per peduncle, pod length (PL), number of grains per pod (NGP), grain length (GRL), grain width, 100-grain weight (W100G), and yield. The heritability values of the traits PL, NGP, GRL, and W100G were all higher than 70%, indicating the possibility of genetic progress with selection. The crosses between the lines IT82D-889 and IT89KD-245, IT85F-1380 and IT89KD-245, and IT89KD-245 and IT98K-1092-1 could result in promising genetic combinations. The characteristics that contributed most to genetic divergence were W100G (49.7%), PL (16.7%), GRL (12.0%), and NGP (9.7%).

Hypercholesterolemia--a disease with expression from childhood

INTRODUCTION

Hypercholesterolemia results from an alteration, genetic or acquired, in lipoprotein metabolism. Evidence that hypercholesterolemia is associated with the atherosclerotic process from childhood justifies the screening of high-risk children and initiation of therapy at preschool ages.

OBJECTIVE

To assess children referred for pediatric consultations due to hypercholesterolemia.

METHODS

Children and adolescents referred for pediatric consultations with a diagnosis of hypercholesterolemia were enrolled. Information on family history and clinical, anthropometric and biochemical parameters was recorded and, when appropriate, molecular study was performed.

RESULTS

A total of 168 children were assessed. Forty-six presented a familial hypercholesterolemia phenotype and in 22 of these, a mutation in the low-density lipoprotein (LDL) receptor gene was identified. The lipid profile of the group with mutations showed significantly higher values of total and non-high-density lipoprotein (HDL) cholesterol compared to the group without mutations (total cholesterol 316.5±75.9 mg/dl vs. 260.9±42,0 mg/dl; non-HDL cholesterol 268.3±72.6 mg/dl vs. 203.5±43.9 mg/dl; p<0.05). Of the total, 55 were prescribed pharmacological therapy and the others underwent diet and exercise interventions only. A greater reduction in LDL cholesterol was observed in individuals under pharmacological therapy compared to those prescribed diet and exercise only (30.3% vs. 18.1%). Drug side effects were insignificant.

CONCLUSION

It is possible to maintain a normal lipid profile in most individuals with familial hypercholesterolemia in order to reduce the risk of early onset of atherosclerosis, which is associated with serious cardiovascular complications from childhood.

Update of the Portuguese Familial Hypercholesterolaemia Study

The main aim of the Portuguese Familial Hypercholesterolaemia Study is to identify the genetic cause of hypercholesterolaemia in individuals with a clinical diagnosis of Familial Hypercholesterolaemia (FH). A total of 1340 blood samples were collected from 482 index patients and 858 relatives with the collaboration of clinicians from several hospitals all over the country. The genetic diagnosis of FH in this study is based on the analyses of three genes: LDLR, APOB and PCSK9. In the last 10 years, the Portuguese FH Study identified a genetic defect in a total of 171 index patients, corresponding to an overall of 48% of the total received cases with clinical diagnosis of FH. Although the Simon Broome FH register criteria have been adapted to our study, 59 patients that did not fulfil all criteria were included in the study and a mutation causing disease was identified in 8 of these patients. In the LDLR gene were found 80 different mutations in 165 unrelated index patients: 159 heterozygous, 3 compounds heterozygous and 3 true homozygous. The APOB p.Arg3527Gln and the PCSK9 p.Asp374His mutation were not found in any of our patients since our last report, but a novel mutation in the APOB gene, predicted to cause a single amino acid substitution p.Tyr3560Cys, was found in one patient. The cascade screening in relatives of these 171 index patients allowed the identification and genetic characterization of a total of 404 FH patients in Portugal.

Molecular diagnosis of familial hypercholesterolemia: an important tool for cardiovascular risk stratification

Familial hypercholesterolemia (FH) is associated with an increased risk of premature coronary heart disease. Molecular identification of these patients can reduce the burden of mortality from cardiovascular disorders simply by the correct identification of the disease early in life, followed by counseling and appropriate lifestyle modifications, and therapeutic measures when required. Recent studies show that, in Portugal, this disease is severely under-diagnosed. After more than 10 years of research through the Portuguese FH Study, it is now possible to translate the original research results into clinical application.

AIMS

The main aims of the present work were to determine whether clinical characterization is sufficient to identify these individuals at high risk of developing CHD and to evaluate the clinical applicability of molecular diagnosis for FH.

METHODS

All patients described in this study were recruited for the Portuguese FH Study. The diagnostic criteria used to select the index patients were adapted from the Simon Broome Heart Research Trust. To analyze the usefulness of the molecular diagnosis, graphs of total and LDL cholesterol values by age were constructed for 622 possible FH patients. The lipid profile of patients genetically identified as having FH, before and under medication, were analyzed to assess whether these patients were receiving appropriate treatment. The data are shown separately for children and adults and for female and male propositi (index cases and hypercholesterolemic relatives), both with and without a detectable mutation in the LDLR gene.

RESULTS

The Portuguese FH Study has already genetically identified 404 individuals (171 index patients and 233 relatives) among more than one thousand individuals sent for study. A total of 78 different mutations in the LDLR gene were found in 171 index patients, 2 different mutations were found in the apoB gene of 4 patients and 2 patients had a unique PCSK9 mutation. Statistical analysis revealed that there are significant differences between total cholesterol (p < 0.001) and apoB (p = 0.026) values in the group of children (male and female) with and without a mutation in LDLR. For female children LDL values were also significantly different (p < 0.001) between subgroups but for male children this difference did not reach statistical significance. In adult women there is a statistically significant difference for total cholesterol (p = 0.049), LDL cholesterol (p = 0.031) and apoB (p = 0.003) values in the subgroups with and without a LDLR mutation. In adult males there is a statistical difference for total cholesterol (p = 0.002). LDL cholesterol (p = 0.003) and apoB (p = 0.0023) in subgroups with and without an LDLR mutation. Nevertheless there was considerable dispersion of values and individually it is not possible to distinguish between patients with and without a mutation in the LDLR gene, based only on lipid profile.

CONCLUSIONS

By analysis of the clinical data of 696 possible FH patients, the present report shows evidence that clinical characterization is not sufficient to distinguish between patients with genetic or environmental dyslipidemia, and so molecular diagnosis is useful in clinical practice, allowing correct identification of FH patients and their relatives, and the early implementation of therapeutic measures to reduce the elevated cardiovascular risk of these patients. In general, molecular diagnosis of FH is feasible and could be obtained in 1-2 months if the technology is available. In Portugal the test will be offered to the population by our Institute at a cost of about 500 euros, like many other genetic tests or exams such as nuclear magnetic resonance.

Familial hypercholesterolaemia in Portugal

Familial hypercholesterolaemia (FH) is characterised clinically by an increased level of circulating LDL cholesterol that leads to lipid accumulation in tendons and arteries, premature atherosclerosis and increased risk of coronary heart disease (CHD). Although Portugal should have about 20,000 cases, this disease is severely under-diagnosed in our country, this being the first presentation of Portuguese data on FH. A total of 602 blood samples were collected from 184 index patients and 418 relatives from several centres throughout Portugal. Fifty-three different mutations were found in 83 index patients, 79 heterozygous and 4 with two defective LDLR alleles. Additionally, 4 putative alterations were found in 8 patients but were not considered mutations causing disease, mainly because they did not co-segregate with hypercholesterolaemia in the families. Three unrelated patients were found to be heterozygous for the APOB(3500) mutation and two unrelated patients were found to be heterozygous for a novel mutation in PCSK9, predicted to cause a single amino acid substitution, D374H. Cascade screening increased the number of FH patients identified genetically to 204. The newly identified FH patients are now receiving counselling and treatment based on the genetic diagnosis. The early identification of FH patients can increase their life expectancy and quality of life by preventing the development of premature CHD if patients receive appropriate pharmacological treatment.

Evaluation of skin sensitization response of dialkyl (C6-C13) phthalate esters

Isolated case reports suggest that dermal contact with some phthalate esters may result in skin sensitization. This issue was investigated in guinea pig sensitization tests, but the results were inconclusive. Consequently, 7 dialkyl phthalate esters, (diisohexyl, diisoheptyl, di(2-ethylhexyl), diisononyl, diisodecyl, diundecyl and ditridecyl phthalates), ranging in carbon number from C6 to C13, were tested in a 104-person panel human repeated insult patch test (HRIPT) using the modified Draize procedure. Test concentrations of 100% were selected for the induction and challenge phases of the HRIPT based upon a 24-h occluded irritation test on 15 panelists. Under the conditions of this HRIPT, no evidence of dermal irritation or sensitization for any of the 7 phthalate esters was observed in the 104-person panel. These HRIPT data provide evidence for the lack of experimental skin sensitization potential for the phthalate esters tested.

Potential biomarkers of benzene exposure

Biological markers or biomarkers of exposure are indicators for the evaluation of the internal dose of a xenobiotic. Biomarkers integrate exposure from all routes and sources. This review presents a short overview of potential biomarkers of benzene exposure currently under investigation, the methodology used for their determination, and experimental findings and their usefulness and specificity in assessing exposure to benzene. Potential biomarkers of benzene exposure are benzene, benzene metabolites, and adducts formed by reactive benzene metabolites with cellular constituents. The potential biomarkers of benzene exposure described in this review are: (1) benzene, the parent hydrocarbon; (2) ring-hydroxylated urinary metabolites, phenol, catechol, hydroquinone, and 1,2,4-trihydroxybenzene; (3) trans,trans-muconic acid, a urinary ring-opened metabolite; (4) N-acetyl-S-(2,5-dihydroxyphenyl)-L-cysteine, a urinary metabolite of benzene, phenol, and hydroquinone; (5) S-phenylmercapturic acid, a glutathione-derived adduct; (6) N7-phenylguanine, a DNA adduct; and (7) S-phenylcysteine and N-phenyl-valine, hemoglobin/protein-derived adducts.

DNA bioprints: simple nonisotopic DNA fingerprints with biotinylated probes

The discovery of multilocal DNA fingerprinting represented a revolution in criminal identification and paternity testing. However, for routine use in clinical laboratories, the standard DNA fingerprint methodology is too complex. We have been successful in the development of a simplified DNA nonisotopic fingerprinting system using biotin-labeled probes which we have called DNA bioprints. To achieve this we explored three main technical features: utilization of biotinylated nonradioactive probes as a simpler substitute for 32P-labeled probes, utilization of oligonucleotide probes as a simpler substitute for recombinant probes, and direct hybridization in the dried agarose gel as a simpler substitute for Southern blots. In this article we review our results in the development of DNA bioprints.