Jorge Pinto-Basto

Inherited and acquired risk factors and their combined effects in pediatric stroke

The aim of this study was to identify hereditary and acquired risk-factors as they are related to the occurrence of stroke in children. We identified 21 children with stroke. A search of the Factor V Leiden mutation, the Factor II G20210A variant, and the thermolabile variant of methylenetetrahydrofolate reductase was performed in patients and in a control group (n = 115). We identified risk factors of acquired and/or hereditary nature for stroke in 19 of 21 children. Eleven children had three or more risk factors, seven had two risk factors, and one child had only one risk factor. We found three carriers (14.3%) of the Factor V Leiden mutation, two carriers (9.5%) of the Factor II G20210A variant, eleven (52.4%) thermolabile variant of methylenetetrahydrofolate reductase heterozygote carriers, and one (4.8%) homozygotes for this variant. Frequencies of the Factor V Leiden mutation and the Factor II variant were higher in patients than in controls, suggesting that these variants are associated with an increased risk of stroke in childhood. Homozygosity for the thermolabile variant of methylenetetrahydrofolate reductase was equally frequent amongst patients and controls. Our study confirms that stroke in children is commonly associated with a combination of multiple risk factors, both genetic and acquired, and that the Factor V Leiden mutation and the Factor II G20210A variant are predisposing factors for this situation.

Osteopathia Striata With Cranial Sclerosis Owing to WTX Gene Defect

Osteopathia striata with cranial sclerosis (OSCS) is an X‐linked dominant condition marked by linear striations mainly affecting the metaphyseal region of the long bones and pelvis in combination with cranial sclerosis. Recently, the disease‐causing gene was identified as the WTX gene (FAM123B), an inhibitor of WNT signaling. A correlation was suggested between the position of the mutation and male lethality. We performed genotype and phenotype studies using 18 patients from eight families with possible WTX gene defects and expanded the clinical spectrum of the affected females. All investigated families diagnosed with OSCS had WTX gene defects. One family had a WTX gene deletion; three of four point mutations were novel. The earlier reported WTX c.1072C>T was detected in four sporadic patients and appears to be a hotspot for mutations. Based on the nature of the mutation present in a surviving male patient, our data do not support the hypothesis raised by Jenkins et al. (2009) regarding a genotype‐phenotype correlation for male lethality. The finding of a gene involved in WNT signaling as the cause of this sclerosing bone phenotype is not unexpected, but further functional studies are needed to explain the specific features. The WTX gene is mutated in different types of cancer, and it remains to be explained why osteopathia striata patients appear not to have an increased risk of cancer. Copyright

Large normal and reduced penetrance alleles in Huntington disease: instability in families and frequency at the laboratory, at the clinic and in the population

Sequeiros J, Ramos EM, Cerqueira J, Costa MC, Sousa A, Pinto‐Basto J, Alonso I. Large normal and reduced penetrance alleles in Huntington disease: instability in families and frequency at the laboratory, at the clinic and in the population.

Genotypes at the APOE and SCA2 loci do not predict the course of multiple sclerosis in patients of Portuguese origin

Multiple sclerosis (MS) is a demyelinating disease that affects about one in 500 young Europeans. In order to test the previously proposed influence of the A PO E and SC A 2 loci on susceptibility to MS, we studied these loci in 243 Portuguese patients and 192 healthy controls and both parents of 92 patients. We did not detect any significant difference when A PO E and SC A 2 allele frequencies of cases and controls were compared, or when we compared cases with different forms of the disease. Disequilibrium of transmission was tested for both loci in the 92 trios, and we did not observe segregation distortion. To test the influence of the A PO E o4 and SC A 2 22 C AGs alleles on severity of disease, we compared age at onset and progression rate between groups with and without those alleles. We did not observe an association of the o4 or the 22 C AG s alleles with rate of progression in our total patient population; allele o4 was associated with increased rate of progression of MS in a subset of patients with less than 10 years of the disease. However, globally in the Portuguese population, the A PO E and SC A2 genes do not seem to be useful in the clinical context as prognostic markers of this disorder.

Autosomal Dominant Spastic Paraplegias: A Review of 89 Families Resulting From a Portuguese Survey

IMPORTANCE Hereditary spastic paraplegias (HSPs) are a group of diseases caused by corticospinal tract degeneration. Mutations in 3 genes (SPG4, SPG3, and SPG31) are said to be the cause in half of the autosomal dominant HSPs (AD-HSPs). This study is a systematic review of families with HSP resulting from a population-based survey. Novel genotype-phenotype correlations were established. OBJECTIVE To describe the clinical, genetic, and epidemiological features of Portuguese AD-HSP families. DESIGN Retrospective medical record review. SETTING A population-based systematic survey of hereditary ataxias and spastic paraplegias conducted in Portugal from 1993 to 2004. PARTICIPANTS Families with AD-HSP. MAIN OUTCOME MEASURE Mutation detection in the most prevalent genes. RESULTS We identified 239 patients belonging to 89 AD-HSP families. The prevalence was 2.4 in 100 000. Thirty-one distinct mutations (26 in SPG4, 4 in SPG3, and 1 in SPG31) segregated in 41% of the families (33.7%, 6.2%, and 1.2% had SPG4, SPG3 and SPG31 mutations, respectively). Seven of the SPG4 mutations were novel, and 7% of all SPG4 mutations were deletions. When disease onset was before the first decade, 31% had SPG4 mutations and 27% had SPG3 mutations. In patients with SPG4 mutations, those with large deletions had the earliest disease onset, followed by those with missense, frameshift, nonsense, and alternative-splicing mutations. Rate of disease progression was not significantly different among patients with SPG3 and SPG4 mutations in a multivariate analysis. For patients with SPG4 mutations, disease progression was worst in patients with later-onset disease. CONCLUSIONS AND RELEVANCE The prevalence of AD-HSP and frequency of SPG3 and SPG4 mutations in the current study were similar to what has been described in other studies except that the frequency of SPG4 deletions was lower. In contrast, the frequency of SPG31 mutations in the current study was rare compared with other studies. The most interesting aspects of this study are that even in patients with early-onset disease the probability of finding a SPG4 mutation was higher than for patients with SPG3 mutations; there was no difference in disease progression with genotype but an association with the age at onset; 7 new SPG4 mutations were identified; and for the first time, to our knowledge, the nature of the SPG4 mutations was found to predict the age at onset.

Alu elements mediate large SPG11 gene rearrangements: further spatacsin mutations.

Purpose:Hereditary spastic paraplegias compose a group of neurodegenerative disorders with a large clinical and genetic heterogeneity. Among the autosomal recessive forms, spastic paraplegia type 11 is the most common.Methods:To better understand the spastic paraplegia type 11 mutation spectrum, we studied a group of 54 patients with hereditary spastic paraplegia. Mutation screening was performed by PCR amplification of SPG11 coding regions and intron boundaries, followed by sequencing. For the detection of large gene rearrangements, we performed multiplex ligation-dependent probe amplification.Results:We report 13 families with spastic paraplegia type 11 carrying either novel or previously identified mutations. We describe a complex entire SPG11 rearrangement and show that large gene rearrangements are frequent among patients with spastic paraplegia type 11. Moreover, we mapped the deletion breakpoints of three different large SPG11 deletions and provide evidence for Alu microhomology-mediated exon deletion.Conclusion:Our analysis shows that the high number of repeated elements in SPG11 together with the presence of recombination hotspots and the high intrinsic instability of the 15q locus all contribute toward making this genomic region more prone to large gene rearrangements. These findings enlarge the amount of data relating repeated elements with neurodegenerative disorders and highlight their importance in human disease and genome evolution.Genet Med 2012:14(1):143–151

A whole genome screen for association with multiple sclerosis in Portuguese patients

Multiple sclerosis (MS) is common in Europe affecting up to 1:500 people. In an effort to identify genes influencing susceptibility to the disease, we have performed a population-based whole genome screen for association. In this study, 6000 microsatellite markers were typed in separately pooled DNA samples from MS patients (n=188) and matched controls (n=188). Interpretable data was obtained from 4661 of these markers. Refining analysis of the most promising markers identified 10 showing potential evidence for association.

Scope of definitions of genetic testing: evidence from a EuroGentest survey

Genetic testing is a term used in different settings, often with very different meanings. There are only very few studies published about the various possible definitions of “genetic testing”, and evidence is lacking from its use in professional practise. The need for precise definitions is particularly felt when producing legislation, policy recommendations or professional guidelines. EuroGentest Unit 3 (Clinical, Community and Public Health Genetics) had, as one of its objectives, to analyse definitions of “genetic testing” and propose consensus working definitions, if possible. To assess what was meant when using this term, in each individual professional context, a questionnaire was developed to evaluate if a consensus definition was desirable and achievable and what items or information should be included in the scope of such a definition. The questionnaire was sent to all EuroGentest partners and other registered users of its website; 135 answers were received, a response rate of 22%. The need for a consensus definition was acknowledged by the vast majority, although there was much less concordance about the possibility of attaining one. Clinical geneticists were the most supportive for context-dependent definitions. Conflicting perspectives arose, however, when discussing the inclusion of some type of tests, material or technology used. At issue seemed to be the distinction between the concepts of genetic material-based testing and genetic information.

Clinical and molecular characterization of Diastrophic Dysplasia in the Portuguese population

Barbosa M, Sousa AB, Medeira A, Lourenço T, Saraiva J, Pinto‐Basto J, Soares G, Fortuna AM, Superti‐Furga A, Mittaz L, Reis‐Lima M, Bonafé L. Clinical and molecular characterization of Diastrophic Dysplasia in the Portuguese population.

Prostate cancer in Cowden syndrome: somatic loss and germline mutation of the PTEN gene.

Germline mutations of PTEN, a tumor suppressor gene, cause a spectrum of autosomal-dominant hamartoma tumor syndrome overgrowth disorders, including Cowden syndrome (CS, MIM#158350) (1). Consensus diagnostic criteria for CS and guidelines for screening of cancer (breast, endometrium, thyroid, kidney, and skin) have beendevelopedby theNational Comprehensive Cancer Network (NCCN) (2). Somatic loss of PTEN has been described in sporadic counterpart tumors of CS as well as sporadic tumors not a component of CS: glioblastoma multiforme, melanoma, lung, pancreas, bladder, colon, and prostate. We report the case of a 58-year-oldmanwithCS.His family history was consistent with autosomal-dominant inheritance: his father, paternal uncle, and son were affected with CS. In addition to macrocephaly, throughout life, the patient had developed multiple tumors: kidney adenocarcinoma, nodular hyperplasia of the thyroid, lesions on the skin and mucous membranes (multiple sclerotic fibromas, papillomatous papules, angiomas), colon polyposis (tubular adenomas, hyperplastic polyps, submucous lipoma), and brain tumors (two meningiomas, multiple angiomas). At the age of 56, after detection of a total prostate-specific antigen value of 24.5 ng/mL, prostate biopsy results revealed, in 60% of the sample, a prostate adenocarcinomawith a combinedGleason score of 8 (4 + 4). High-grade prostate intraepithelial neoplasia was present in the remaining sample tissue. At the time of diagnosis, vertebral column metastasis (D3, D4, D5) was already evident. This cancer had developed rapidly and aggressively: at the age of 54, digital rectal examination showedaglobally voluminousprostate. Total prostate-specific antigen was normal (2.62 ng/mL). PTEN sequencing performed on DNA extracted from lymphocytes revealed a previously described heterozygous nonsense mutation, c.388C>T (p.Arg130X), confirming the clinical diagnosis of CS. Thismutation was also identified in the patient’s son. In DNA extracted from the paraffin-embedded prostate cancer biopsy samples, it was only possible to reliably amplify and sequence exons 1, 3, 4, and 5. This revealed loss of the wild-type allele of PTEN. Because no more neoplastic tissue was available, it was not possible to refine the molecular analysis of the PTEN gene or to analyze other genes associated with prostate cancer initiation and/or progression. PTEN mutations have been described in 30% of primary prostate tumors, suggesting a role for this gene in the initiation of prostate cancer (3). Somatic PTEN mutations are