Seven DNA polymorphisms in the LDL receptor gene: application to the study of familial hypercholesterolemia in Spain

We have performed restriction fragment length polymorphism (RFLP) analysis at the low density lipoprotein receptor (LDLR) locus in order to investigate the molecular genetics of familial hypercholesterolemia (FH) in Spain. Firstly, a sample of 50 unrelated patients with a clinical diagnosis of FH was screened for the presence of major rearrangements at this locus by Southern blot analysis of Bgt II digested genomic DNA. Four different mutations were detected, accounting for 8% of the mutant alleles in the Spanish FH sample. Then, we determined the relative allele frequency and estimated linkage disequilibrium between seven RFLPs of the LDLR gene in the remaining 46 FH patients and in 61 normolipidemic controls. Hindi, Avail, Pvu II, Msp I, and Nco I are the most polymorphic sites with individual PIC values higher than 0.28, whereas the Taq I and Stu I sites display low levels of polymorphism. The usefulness of the seven RFLPs to confirm a clinical diagnosis of FH was investigated in 15 FH-families, consisting of 118 individuals, in whom the presence of Familial Defective Apolipoprotein B-100 (FDB) due to the apoB₃₅₀₀ mutation was excluded. Independent haplotypes were constructed for 71 chromosomes: 15 FH and 56 control haplotypes. A total of 14 different haplotypes was found. In 12 families, clinical diagnosis of FH was confirmed by cosegregation analysis, which makes these RFLPs useful for studying the inheritance of the LDLR gene in 80% of Spanish families with FH. Comparison of haplotypes found in the Spanish sample with those found in Swiss and Norwegians suggests heterogeneity of haplotypes among European populations.     

The evolution of sex chromosomes in the genus <Emphasis Type="Italic">Rumex</Emphasis> (Polygonaceae): Identification of a new species with heteromorphic sex chromosomes

The structural features and evolutionary state of the sex chromosomes of the XX/XY species of Rumex are unknown. Here, we report a study of the meiotic behaviour of the XY bivalent in Rumex acetosella and R. suffruticosus, a new species which we describe cytogenetically for the first time in this paper, and also that of the XY₁Y₂ trivalent of R. acetosa by both conventional cytogenetic techniques and analysis of synaptonemal complex formation. Fluorescent in situ hybridization with satellite DNA and rDNA sequences as probes was used to analyse the degree of cytogenetic differentiation between the X and Y chromosomes in order to depict their evolutionary stage in the three species. Contrasting with the advanced state of genetic differentiation between the X and the Y chromosomes in R. acetosa, we have found that R. acetosella and R. suffruticosus represent an early stage of genetic differentiation between sex chromosomes. Our findings further demonstrate the usefulness of the genus Rumex as a model for analysing the evolution of sex chromosomes in plants, since within this genus it is now possible to study the different levels of genetic differentiation between the sex chromosomes and to analyse their evolutionary history from their origin.     

CDKN2A mutations in Spanish cutaneous malignant melanoma families and patients with multiple melanomas and other neoplasia

The CDKN2A gene has been implicated in cutaneous malignant melanoma (CMM) in about 40% of families with linkage to chromosome 9p21, while a small proportion of families have mutations in the CDK4 gene. In order to estimate the importance of these genes in the predisposition to CMM in Spanish families and patients we have analysed, by SSCA, a total of 56 subjects belonging to 34 CMM families, and nine patients with multiple CMM and other neoplasia. We have detected germline CDKN2A mutations in six out of the 34 families (17%). A frameshift mutation (358delG) and four missense mutations (G59V, G101W (two cases), D84Y, and R87W) were identified. Five CMM patients from different families (14%) carried the A148T variant, which is known not to affect p16 activity. No mutations were detected in the patients with multiple CMM or other neoplasms. We have not found mutations either in exon 1 beta of the CDKN2A gene or in exon 2A of CDK4. Linkage analysis of the 9p21 region showed exclusion for one of the families for CMM and for four families for CMM/dysplastic naevi. This study indicates a small role for CDKN2A in Spanish CMM families and suggests that other genes are also responsible for CMM predisposition.     

Mutations in TRAPPC11 are associated with a congenital disorder of glycosylation

Congenital disorders of glycosylation (CDG) are a heterogeneous and rapidly growing group of diseases caused by abnormal glycosylation of proteins and/or lipids. Mutations in genes involved in the homeostasis of the endoplasmic reticulum (ER), the Golgi apparatus (GA), and the vesicular trafficking from the ER to the ER–Golgi intermediate compartment (ERGIC) have been found to be associated with CDG. Here, we report a patient with defects in both N‐ and O‐glycosylation combined with a delayed vesicular transport in the GA due to mutations in TRAPPC11, a subunit of the TRAPPIII complex. TRAPPIII is implicated in the anterograde transport from the ER to the ERGIC as well as in the vesicle export from the GA. This report expands the spectrum of genetic alterations associated with CDG, providing new insights for the diagnosis and the understanding of the physiopathological mechanisms underlying glycosylation disorders.     

Nasal Septal and Premaxillary Developmental Integration: Implications for Facial Reduction in Homo

The influence of the chondrocranium in craniofacial development and its role in the reduction of facial size and projection in the genus Homo is incompletely understood. As one component of the chondrocranium, the nasal septum has been argued to play a significant role in human midfacial growth, particularly with respect to its interaction with the premaxilla during prenatal and early postnatal development. Thus, understanding the precise role of nasal septal growth on the facial skeleton is potentially informative with respect to the evolutionary change in craniofacial form. In this study, we assessed the integrative effects of the nasal septum and premaxilla by experimentally reducing facial length in Sus scrofa via circummaxillary suture fixation. Following from the nasal septal‐traction model, we tested the following hypotheses: (1) facial growth restriction produces no change in nasal septum length; and (2) restriction of facial length produces compensatory premaxillary growth due to continued nasal septal growth. With respect to hypothesis 1, we found no significant differences in septum length (using the vomer as a proxy) in our experimental (n = 10), control (n = 9) and surgical sham (n = 9) trial groups. With respect to hypothesis 2, the experimental group exhibited a significant increase in premaxilla length. Our hypotheses were further supported by multivariate geometric morphometric analysis and support an integrative relationship between the nasal septum and premaxilla. Thus, continued assessment of the growth and integration of the nasal septum and premaxilla is potentially informative regarding the complex developmental mechanisms that underlie facial reduction in genus Homo evolution. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.     

Interaction of Leishmania mexicana promastigotes with the plasminogen–plasmin system

The binding of human plasminogen and plasmin to the promastigote form of Leishmania mexicana was investigated. L. mexicana was capable to bind both molecules, the binding being inhibited by -aminocaproic acid. Scatchard plot analysis revealed a dissociation constant (K_d) value of 2.4±0.8 μM and 0.9±0.1×10⁴ binding sites per cell for plasminogen and a K_d value of 1.2±0.4 μM and 1.6±0.2×10⁵ binding sites per cell for plasmin. C-terminal lysine residues are involved in plasminogen binding to cells, since carboxypeptidase B treatment reduced this binding by 34%. Ligand blotting analysis showed a group of proteins, with molecular masses between 105 and 115 kDa, capable to interact with plasminogen. Zymogram analysis showed that the protease activity acquired by L. mexicana, due to the interaction with either plasminogen or plasmin, comprises an important fraction of the total protease activity at pH 7.7. Plasminogen activation by tissue-type plasminogen activator (t-PA) was enhanced by the presence of L. mexicana promastigotes. These results raise the question whether the interaction of L. mexicana with components of the fibrinolytic system is involved in the virulence of the parasite.     

Frequency of HLA-A, -B and -DRB1 specificities and haplotypic associations in the population of Castilla y León (northwest-central Spain)

The frequencies of human leukocyte antigen (HLA) class I and class II specificities and haplotypic associations were determined in 1940 unrelated donors from Castilla y León and compared with other Iberian, Mediterranean and European populations. Specificities were determined using polymerase chain reaction reverse sequence-specific oligonucleotide or polymerase chain reaction sequence-specific primer techniques. In the analysis, 19, 29 and 13 specificities were found for HLA-A, -B and -DRB1, respectively, with HLA-A*02 (26%), -A*01 (11%), -B*44 (16%), -B*35 (10%), -DRB1*07 (16%) and -DRB1*13 (14%) showing the highest frequencies. In addition, 10 common HLA-A-B-DRB1 haplotypic associations were observed, A*01-B*08-DRB1*03 (3%) and A*29-B*44-DRB1*07 (3%) being the most frequent ones. These findings indicate that the population of Castilla y León is genetically equidistant from the Portuguese and other Spanish populations and shares a common origin with other Iberian populations, in which European, Mediterranean and North African genetic components are present; this is in agreement with the historical and genetic background of the population. These data contribute to a better understanding of the genetic structure of the Iberian Peninsula and provide a healthy control population from our region that should be useful for the study of disease associations.     

Welfare reform and the health of young children: a sentinel survey in 6 US cities

CONTEXT: Welfare reform under the 1996 Personal Responsibility and Work Opportunity Reconciliation Act replaced entitlement to cash assistance for low-income families with Temporary Assistance to Needy Families, thereby terminating or decreasing cash support for many participants. Proponents anticipated that continued receipt of food stamps would offset the effects of cash benefit losses, although access to food stamps was also restricted. OBJECTIVE: To examine associations of loss or reduction of welfare with food security and health outcomes among children aged 36 months or younger at 6 urban hospitals and clinics. DESIGN AND SETTING: A multisite retrospective cohort study with cross-sectional surveys at urban medical centers in 5 states and Washington, DC, from August 1998 through December 2000. PARTICIPANTS: The caregivers of 2718 children aged 36 months or younger whose households received welfare or had lost welfare through sanctions were interviewed at hospital clinics and emergency departments. MAIN OUTCOME MEASURES: Household food security status, history of hospitalization, and, for a subsample interviewed in emergency departments, whether the child was admitted to the hospital the day of the visit. RESULTS: After controlling for potential confounding factors, children in families whose welfare was terminated or reduced by sanctions had greater odds of being food insecure (adjusted odds ratio [AOR], 1.5; 95% confidence interval [CI], 1.1-1.9), of having been hospitalized since birth (AOR, 1.3; 95% CI, 1.0-1.7) and, for the emergency department subsample, of being admitted the day of an emergency department visit (AOR, 1.9; 95% CI, 1.2-3.0) compared with those without decreased benefits. Children in families whose welfare benefits were decreased administratively because of changes in income or expenses had greater odds of being food insecure (AOR, 1.5; 95% CI, 1.1-2.2) and of being admitted the day of an emergency department visit (AOR, 2.8; 95% CI, 1.4-5.6). Receiving food stamps does not mitigate the effects of the loss or reduction of welfare benefits on food security or hospitalizations. CONCLUSION: Terminating or reducing welfare benefits by sanctions, or decreasing benefits because of changes in income or expenses, is associated with greater odds that young children will experience food insecurity and hospitalizations.