Camila Matzenbacher Bittar

Screening of RB1 Alterations in Brazilian Patients With Retinoblastoma and Relatives With Retinoma: Phenotypic and Genotypic Associations

PURPOSE To identify constitutional alterations of the retinoblastoma 1 gene (RB1) in two cohorts of Brazilian patients with retinoblastoma and to analyze genotype-phenotype associations. METHODS Molecular screening was carried out by direct sequencing of the 27 RB1 exons and flanking regions in blood DNA of 71 patients with retinoblastoma and 4 relatives with retinoma, and with multiplex ligation-dependent probe amplification (MLPA) in 21 patients. The presumed impact of nucleotide substitutions on the structure of the retinoblastoma protein (pRB) was predicted by Polymorphism Phenotyping-2 (PolyPhen-2). Kaplan-Meier and log-rank test were used for estimating 60-month survival rates. RESULTS One hundred two nucleotide substitutions were detected, 92 substitutions in 59 patients with retinoblastoma and 10 substitutions in 4 individuals with retinoma. Eight substitutions were novel. The majority of substitutions were intronic (86.2%). More than one substitution was present in 37.3% of patients. Twenty-one duplications and 11 deletions were found in 12 patients; some of which with both types of alterations. Duplications/deletions were found in four patients lacking constitutional alterations when analyzed by sequencing, and in eight patients carrying one or more polymorphic intronic substitutions. The global 60-month survival rate in patients was 91.8% (Confidence Interval95% = 85.0 - 99.1). Significant, lower survival rates were found in extraocular presentation (81.0%) versus intraocular tumors (P = 0.014), first enucleation after 1 month following diagnosis (80.9%) versus earlier first enucleation (P = 0.020), and relapse (100.0%) versus absence of relapse (P = 0.0005). CONCLUSIONS Fifteen substitutions (4 intronic and 11 exonic) were identified as probably or likely pathogenic. Four of these 11 exonic substitutions were novel. Survival rates, however, were not affected by presence of these probably or likely pathogenic alterations, most of which not found in patients with retinoblastoma from other Latin American countries. These differences might be related to the different ethnic composition of the Latin American cohorts. Portuguese Abstract.

Prevalence of Hispanic BRCA1 and BRCA2 mutations among hereditary breast and ovarian cancer patients from Brazil reveals differences among Latin American populations.

Germline mutations in BRCA1 or BRCA2 (BRCA) are responsible for 5-15% of breast (BC) and ovarian cancers (OC), predisposing to the development of early onset and often multiple primary tumors. Since mutation carriers can benefit from risk-reducing interventions, the identification of individuals with hereditary breast and ovarian cancer (HBOC) syndrome has a significant clinical impact. We assessed whether a panel assay for recurrent Hispanic BRCA mutations (HISPANEL) has an adequate breadth of coverage to be suitable as a cost effective screening tool for HBOC in a cohort of patients from Southern Brazil. A multiplex, PCR-based panel was used to genotype 232 unrelated patients for 114 germline BRCA mutations, finding deleterious mutations in 3.5% of them. This mutation prevalence is within the range detected by the HISPANEL among BC patients unselected for family history in other Latin American settings. The HISPANEL would have accounted for 27% of the BRCA mutations detected by complete sequencing in a comparison cohort (n = 193). This prevalence may be region-specific since significant differences in population structure exist in Brazil. Comprehensive analysis of BRCA in a larger set of HBOC patients from different Brazilian regions is warranted, and the results could inform customization of the HISPANEL as an affordable mutation screening tool.

Emerging treatment options for the mucopolysaccharidoses

Roberto Giugliani1–6 Andressa Federhen1,4 Andre Anjos Silva1,5 Camila Matzenbacher Bittar1,5 Carolina Fischinger Moura de Souza1 Cristina Brinckmann Oliveira Netto1 Fabiana Quoos Mayer2,7 Guilherme Baldo1,2,8 Ursula Matte1–5 1Medical Genetics Service, 2Gene Therapy Center, Hospital de Clinicas (HCPA), Porto Alegre, RS, Brazil; 3Department of Genetics, 4Postgraduate Program in Child and Adolescent Health, 5Postgraduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil; 6National Institute of Population Medical Genetics (INAGEMP), Porto Alegre, RS, Brazil; 7Fundacao Estadual de Pesquisa Agropecuaria (FEPAGRO), Eldorado do Sul, RS, Brazil; 8Department of Biophysics, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil

The germline mutational landscape of BRCA1 and BRCA2 in Brazil

The detection of germline mutations in BRCA1 and BRCA2 is essential to the formulation of clinical management strategies, and in Brazil, there is limited access to these services, mainly due to the costs/availability of genetic testing. Aiming at the identification of recurrent mutations that could be included in a low-cost mutation panel, used as a first screening approach, we compiled the testing reports of 649 probands with pathogenic/likely pathogenic variants referred to 28 public and private health care centers distributed across 11 Brazilian States. Overall, 126 and 103 distinct mutations were identified in BRCA1 and BRCA2, respectively. Twenty-six novel variants were reported from both genes, and BRCA2 showed higher mutational heterogeneity. Some recurrent mutations were reported exclusively in certain geographic regions, suggesting a founder effect. Our findings confirm that there is significant molecular heterogeneity in these genes among Brazilian carriers, while also suggesting that this heterogeneity precludes the use of screening protocols that include recurrent mutation testing only. This is the first study to show that profiles of recurrent mutations may be unique to different Brazilian regions. These data should be explored in larger regional cohorts to determine if screening with a panel of recurrent mutations would be effective.

Vitamin D Status and VDR Genotype in NF1 Patients: A Case-Control Study from Southern Brazil

Neurofibromatosis type 1 (NF1) patients are more likely to have vitamin D deficiency when compared to the general population. This study aimed to determine the levels of 25-OH-vitamin D [25(OH)D] in individuals with NF1 and disease-unaffected controls and analyze FokI and BsmI VDR gene polymorphisms in a case and in a control group. Vitamin D levels were compared between a group of 45 NF1 patients from Southern Brazil and 45 healthy controls matched by sex, skin type, and age. Genotypic and allelic frequencies of VDR gene polymorphisms were obtained from the same NF1 patients and 150 healthy controls. 25(OH)D deficiency or insufficiency was not more frequent in NF1 patients than in controls (p = 0.074). We also did not observe an association between FokI and BsmI VDR gene polymorphisms and vitamin D levels in NF1 patients, suggesting that their deficient or insufficient biochemical phenotypes are not associated with these genetic variants. The differences between the groups in genotypic and allelic frequencies for FokI and BsmI VDR gene polymorphisms were small and did not reach statistical significance. These polymorphisms are in partial linkage disequilibrium and the haplotype frequencies also did not differ in a significant way between the two groups (p = 0.613).

BRCA1 and BRCA2 mutational profile and prevalence in hereditary breast and ovarian cancer (HBOC) probands from Southern Brazil: Are international testing criteria appropriate for this specific population?

[This corrects the article DOI: 10.1371/journal.pone.0187630.].

Adherence to Treatment of Phenylketonuria: A Study in Southern Brazilian Patients

Introduction:Phenylketonuria (PKU) is caused by the deficient activity of phenylalanine hydroxylase.Aim:To identify the factors associated with treatment adherence among patients with PKU seen at a southern Brazil reference center.Methodology:A cross-sectional, outpatient-based study including 56 patients with PKU (median age, 12 years) for whom a Phe-restrict diet plus specific metabolic formula have been prescribed. Patients were considered adherent or nonadherent depending on the median phenylalanine concentration for the 12 months prior to study and target levels of phenylalanine for each age range (<13 years = ≤360 µmol/L; ≥13 years = ≤900 µmol/L). Data were collected through a review of patient’s medical records and a set of interviews with patients and their relatives.Results:Eighteen patients (32.1%; ≥13 years, 11) were classified as treatment adherent. Among all factors analyzed, only mental retardation, living with parents, and level of maternal education were associated with adherence to treatm...

Screening and characterization of BRCA2 c.156_157insAlu in Brazil: results from 1380 individuals from the South and Southeast.

Portuguese immigration to Brazil occurred in several waves and greatly contributed to the genetic composition of current Brazilian population. In this study, we evaluated the frequency of a Portuguese founder Alu insertion in BRCA2 exon 3 (c.156_157insAlu) among individuals fulfilling Hereditary Breast and Ovarian Cancer (HBOC) syndrome criteria in 1,380 unrelated families originated from three distinct Brazilian States. We identified the c.156_157insAlu BRCA2 mutation in nine (9/1,380; 0.65%) probands analised. In carrier probands, European ancestry had the highest proportion (80%), followed by the African (10%) and Amerindian and in most families with the rearrangement, haplotype analyses were compatible with the Portuguese ancestral haplotype. In conclusion, the present study reports a low albeit relevant frequency of the Portuguese BRCA2 founder mutation c.156_157insAlu in Brazilian patients at-risk for HBOC Brazilian population.

Correction: Biotinidase deficiency: Genotype-biochemical phenotype association in Brazilian patients

[This corrects the article DOI: 10.1371/journal.pone.0177503.].

Abstract 4282: GermlineTP53p.R337H mutations and Li-Fraumeni syndrome: A new variant form of the disease

The founder germline TP53 mutation, p.R337H, was detected in South and Southern Brazil in families with Li-Fraumeni Syndrome (LFS). The aim of this study was to estimate the burden and patterns of cancer in p.R337H carriers and other germline TP53 mutations. We analyzed data on 539 individuals from the LFS/LFL database from A.C. Camargo Cancer Center in Sao Paulo, Brazil and compared to International Agency for Research on Cancer (IARC) germline TP53 mutations database (R17). A total of 144 p.R337H carriers have developed 147 cancers (16.7% multiple primaries). The most frequent malignancies were soft tissue sarcoma (STS; 25.9%), breast cancer (24.5%) and adrenocortical carcinoma (ACC; 17.7%). Compared to IARC database, p.R337H carriers had a higher risk of ACC and STS, a lower risk of brain tumors and osteosarcomas (P Citation Format: Claire Freycon, Kelvin Cesar De Andrade, Amina Yacouba, Maria Nirvana Formiga, Camila Bittar, Karina Miranda Santiago, Sharon Savage, Patricia Ashton-Prolla, Pierre Hainaut, Maria Isabel Achatz. Germline TP53 p.R337H mutations and Li-Fraumeni syndrome: A new variant form of the disease [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4282. doi:10.1158/1538-7445.AM2017-4282