22q11.2 Deletion Syndrome: Influence of Parental Origin on Clinical Heterogeneity.

22q11.2 deletion syndrome (22q11.2DS) shows significant clinical heterogeneity.

Identification of single nucleotide variants in SLC26A9 gene in patients with cystic fibrosis (p.Phe508del homozygous) and its association to Orkambi® (Lumacaftor and Ivacaftor) response in vitro.

Background: Since patients with cystic fibrosis with different Cystic Fibrosis Transmembrane Regulator (CFTR) genotypes present a wide response variability for modulator drugs such as Orkambi®, it is important to screen variants in candidate genes with an impact on precision and personalized medicine, such as Solute Carrier Family 26, member 9 (SLC26A9) gene.

Methods: Sanger sequencing for the exons and intron-exon boundary junctions of the SLC26A9 gene was employed in nine individuals with p.Phe508del homozygous genotype for the CFTR gene who were not under CFTR modulators therapy.

RFC1-Related Disorder: In Vivo Evaluation of Spinal Cord Damage.

Background: RFC1-related disorder is a novel heredodegenerative condition with a broad phenotypic spectrum. Its neuropathological bases are not yet fully understood, particularly regarding the pattern, extent, and clinical relevance of spinal cord (SC) damage.

Objectives: The objectives were to determine the SC structural signature in RFC1-related disorder in vivo and to identify potential clinical correlates for these imaging abnormalities.

DRPLA: An unusual disease or an underestimated cause of ataxia in Brazil?

Background: Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant spinocerebellar ataxia caused by pathological expansion of CAG trinucleotide repeats in the ATN1 gene. Most cases were described in patients from Japanese ancestry who presented with adult-onset progressive cerebellar ataxia associated with cognitive impairment, choreoathetosis and other movement disorders. DRPLA has been rarely described in Brazilian patients.

Slowly progressive behavioral frontotemporal dementia syndrome in a family co-segregating the C9orf72 expansion and a Synaptophysin mutation.

Introduction: Synaptophysin, already related to X-linked intellectual disability, is expressed mainly in the central nervous system. Studies in humans indicate that the downregulation of synaptophysin could be involved in the development of dementia. Our study presents the first familial case of behavioral variant frontotemporal dementia associated with the co-occurrence of the repeat expansion in C9orf72 and a pathogenic variant in the SYP gene.

Brain Structural Signature of RFC1-Related Disorder.

Background: The cerebellar ataxia, neuropathy, and vestibular areflexia syndrome was initially described in the early 1990s as a late-onset slowly progressive condition. Its underlying genetic cause was recently mapped to the RFC1 gene, and additional reports have expanded on the phenotypic manifestations related to RFC1, although little is known about the pattern and extent of structural brain abnormalities in this condition.

Objective: The aim is to characterize the structural signature of brain damage in RFC1-related disorder, correlating the findings with clinical symptoms and normal brain RFC1 expression.

Diagnostic Yield of Whole Exome Sequencing for Adults with Ataxia: a Brazilian Perspective.

Previous studies using whole exome sequencing (WES) have shown that a significant proportion of adult patients with undiagnosed ataxia in European and North American cohorts have a known genetic cause. Little is known about the diagnostic yield of WES in non-Caucasian ataxic populations. Herein, we used WES to investigate a Brazilian cohort of 76 adult patients with idiopathic ataxia previously screened for trinucleotide expansions in known ataxia genes.

CAG repeats ≥ 34 in Ataxin-1 gene are associated with amyotrophic lateral sclerosis in a Brazilian cohort.

Little is known about the genetic basis of amyotrophic lateral sclerosis (ALS) outside Europe and US. In this study, we investigated whether intermediate CAG expansions at ATXN1 were associated to ALS in the Brazilian population. To accomplish that, representative samples from 411 unrelated patients and 436 neurologically normal controls from 6 centers spread over the territory were genotyped to quantify ATXN1 expansions.

Frequency and Genetic Profile of Compound Heterozygous Friedreich's Ataxia Patients-the Brazilian Experience.

Friedreich ataxia (FRDA) is the most common autosomal recessive ataxia in Caucasian populations. It is caused by a homozygous GAA expansion in the first intron of the frataxin gene (FXN) (OMIM: 606829) in 96% of the affected individuals. The remaining patients have a GAA expansion in one allele and a point mutation in the other.

Intermediate-length CAG repeat in ATXN2 is associated with increased risk for amyotrophic lateral sclerosis in Brazilian patients.

Intermediate-length cytosine-adenine-guanine nucleotide repeat expansions in the ATXN2 gene (which encodes for the protein Ataxin-2) have been linked to increased risk for amyotrophic lateral sclerosis (ALS) in different populations. There is no such study in the Brazilian population, which has a mixed ethnic background. We have thus selected 459 patients with ALS (372 Sporadic ALS and 87 Familial ALS) and 468 control subjects from 6 Brazilian centers to investigate this point.

The frequency of the C9orf72 expansion in a Brazilian population.

GC hexanucleotide repeat expansions in the C9orf72 gene seem to be the cause of numerous cases of amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD). In this study, we investigated the presence of the GC repeat expansion in 463 Brazilian probands, of whom 404 had ALS/motor neuron disease and 67 FTD, and in 63 healthy controls in the southeastern region of Brazil. The highest frequencies of the C9orf72 mutation were in the ALS-FTD group (50% of familial and 17.

Burkholderia cepacia complex in cystic fibrosis in a Brazilian reference center.

The Burkholderia cepacia complex (BCC) can cause a severe decline in lung function in cystic fibrosis (CF). Our objective was to determine the BCC prevalence and to evaluate its clinical impact on CF. Clinical and laboratory variables were determined for CF patients with BCC (Group-A = 50 patients) and without BCC (Group-B = 134 patients).

Frequency of the allelic variant c.1150T > C in exon 10 of the fibroblast growth factor receptor 3 (FGFR3) gene is not increased in patients with pathogenic mutations and related chondrodysplasia phenotypes.

Mutations in the FGFR3 gene cause the phenotypic spectrum of FGFR3 chondrodysplasias ranging from lethal forms to the milder phenotype seen in hypochondroplasia (Hch). The p.N540K mutation in the FGFR3 gene occurs in ∼70% of individuals with Hch, and nearly 30% of individuals with the Hch phenotype have no mutations in the FGFR3, which suggests genetic heterogeneity.

TNF-alpha polymorphisms as a potential modifier gene in the cystic fibrosis.

Modifier genes, as the TNF-α gene, can modulate the cystic fibrosis (CF) severity. Thus, -238G>A and -308G>A polymorphisms of TNF-α gene were analyzed as modifiers of CF. In this context, the present study enrolled 49 CF patients (diagnosis performed by sweat test and complete CFTR screening).

CFTR genotype and clinical outcomes of adult patients carried as cystic fibrosis disease.

Background: There are nearly 2000 cystic fibrosis transmembrane regulator (CFTR) mutations that cause cystic fibrosis (CF). These mutations are classified into six classes; on the one hand, the first three classes cause severe disease involvement in early childhood, on the other hand, the Class IV, V and VI mutations cause minor severe disease in the same age. Nowadays, with therapeutic advances in CF management and competence of pediatricians, physicians of adults have to deal with two groups of CF patients: (i) adults diagnosed in childhood with severe mutations and (ii) adults who initiated symptoms in adulthood and with Class IV, V and VI mutations.

Normal ATXN3 Allele but Not CHIP Polymorphisms Modulates Age at Onset in Machado-Joseph Disease.

Background: Age at onset (AO) in Machado-Joseph disease (MJD) is closely associated with the length of the CAG repeat at the mutant ATXN3 allele, but there are other intervening factors. Experimental evidence indicates that the normal ATXN3 allele and the C-terminal heat shock protein 70 (Hsp70)-interacting protein (CHIP) may be genetic modifiers of AO in MJD.

Methods: To investigate this hypothesis, we determined the length of normal and expanded CAG repeats at the ATXN3 gene in 210 unrelated patients with MJD.

Measurements of CFTR-mediated Cl- secretion in human rectal biopsies constitute a robust biomarker for Cystic Fibrosis diagnosis and prognosis.

Background: Cystic Fibrosis (CF) is caused by ∼1,900 mutations in the CF transmembrane conductance regulator (CFTR) gene encoding for a cAMP-regulated chloride (Cl(-)) channel expressed in several epithelia. Clinical features are dominated by respiratory symptoms, but there is variable organ involvement thus causing diagnostic dilemmas, especially for non-classic cases.

Methodology/principal Findings: To further establish measurement of CFTR function as a sensitive and robust biomarker for diagnosis and prognosis of CF, we herein assessed cholinergic and cAMP-CFTR-mediated Cl(-) secretion in 524 freshly excised rectal biopsies from 118 individuals, including patients with confirmed CF clinical diagnosis (n=51), individuals with clinical CF suspicion (n=49) and age-matched non-CF controls (n=18).

The ACE gene D/I polymorphism as a modulator of severity of cystic fibrosis.

Background: Cystic Fibrosis (CF) is a monogenic disease with complex expression because of the action of genetic and environmental factors. We investigated whether the ACE gene D/I polymorphism is associated with severity of CF.

Methods: A cross-sectional study was performed, from 2009 to 2011, at University of Campinas - UNICAMP.

A combined voxel-based morphometry and 1H-MRS study in patients with Friedreich's ataxia.

Friedreich's ataxia (FA) is the most frequent autosomal recessive ataxia and essentially considered a disease of the dorsal root ganglia and spinal cord. It is caused by homozygous GAA expansions in the Frataxin gene in most cases. Although only a few studies have addressed cerebral involvement in FA, cognitive symptoms have lately been emphasized.

Polymorphisms in methylenetetrahydrofolate reductase gene (MTHFR) and the age of onset of sporadic colorectal adenocarcinoma.

Background And Aims: Evidence is accumulating for a role of folate in the aetiology of colorectal cancer (CRC). The methylenetetrahydrofolate reductase (MTHFR) gene, involved in folate metabolism, is polymorphic in humans. Since it is unknown whether the MTHFR C677T and A1298C polymorphisms alter the risk for CRC, this was the aim of our study.