New and Known Variants in a Series of Latin American Patients with Holoprosencephaly.

Holoprosencephaly (HPE) is the failure of the embryonic forebrain to develop into 2 hemispheres promoting midline cerebral and facial defects. The wide phenotypic variability and causal heterogeneity make genetic counseling difficult. Heterozygous variants with incomplete penetrance and variable expressivity in the , , , and genes explain ∼25% of the known causes of nonchromosomal HPE.

Copy Number Variations in a Cohort of 420 Individuals with Neurodevelopmental Disorders From the South of Brazil.

Chromosomal microarray (CMA) is now recommended as first tier for the evaluation in individuals with unexplained neurodevelopmental disorders (ND). However, in developing countries such as Brazil, classical cytogenetic tests are still the most used in clinical practice, as reflected by the scarcity of publications of microarray investigation in larger cohorts. This is a retrospective study which analyses the reading files of CMA and available clinical data from 420 patients from the south of Brazil, mostly children, with neurodevelopmental disorders requested by medical geneticists and neurologists for diagnostic purpose.

Long contiguous stretches of homozygosity detected by chromosomal microarrays (CMA) in patients with neurodevelopmental disorders in the South of Brazil.

Background: Currently, chromosomal microarrays (CMA) are recommended as first-tier test in the investigation of developmental disorders to examine copy number variations. The modern platforms also include probes for single nucleotide polymorphisms (SNPs) that detect homozygous regions in the genome, such as long contiguous stretches of homozygosity (LCSH) also named runs of homozygosity (ROH). LCHS are chromosomal segments resulting from complete or segmental chromosomal homozygosity, which may be indicative of uniparental disomy (UPD), consanguinity, as well as replicative DNA repair events, however also are common findings in normal populations.

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.

CBS mutations are good predictors for B6-responsiveness: A study based on the analysis of 35 Brazilian Classical Homocystinuria patients.

Background: Classical homocystinuria (HCU) is a monogenic disease caused by the deficient activity of cystathionine β-synthase (CβS). The objective of this study was to identify the CBS mutations in Brazilian patients with HCU.

Methods: gDNA samples were obtained for 35 patients (30 families) with biochemically confirmed diagnosis of HCU.

Biotinidase deficiency: clinical and genetic studies of 38 Brazilian patients.

Background: Biotinidase deficiency (BD) is an inborn error of metabolism in which some genetic variants correlate with the level of enzyme activity. Biotinidase activity, however, may be artifactually low due to enzyme lability, premature birth, and jaundice; this hinders both phenotypic classification and the decision to implement therapy. This study sought to characterize the clinical and genetic profile of a sample of Brazilian patients exhibiting reduced biotinidase activity.

Rare nasal cleft in a patient with holoprosencephaly due to a mutation in the ZIC2 gene.

Background: Holoprosencephaly (HPE) is a spectrum of midline malformations of the prosencephalon generally reflected in a continuum of midline facial anomalies. Patients with mutation in the ZIC2 gene usually present a normal or mildly dysmorphic face associated with a severe brain malformation. Here we present a rare unilateral nasal cleft (Tessier cleft n.

Type 1 diabetes in a patient with Ellis-van Creveld syndrome.

Context: Ellis-van Creveld (EVC) syndrome is a rare autosomal recessive disease characterized by disproportionate short stature, narrow thorax, postaxial polydactyly, nail and tooth abnormalities and congenital heart disease.

Case Report: The patient was a 22-year-old Caucasian man, the third child of consanguineous parents. He received the diagnosis of insulin-dependent diabetes mellitus (DM) at 16 years of age, and around one year later, he underwent surgery to correct a partial atrioventricular septal defect.

Fibular dimelia and mirror polydactyly of the foot in a girl presenting additional features of the VACTERL association.

Context: The association between fibular dimelia and mirror polydactyly of the foot is considered to be a very rare lower-limb abnormality. On the other hand, VACTERL is an acronym for a nonrandom association of congenital anomalies for which the etiology is still poorly understood.

Case Report: The patient was a seven-month-old white girl whose mother had used misoprostol in the second month of pregnancy to induce abortion.

Additional features in a new case of a girl presenting brachyphalangy, polydactyly and tibial aplasia/hypoplasia.

Brachyphalangy, polydactyly and tibial aplasia/hypoplasia is a rare autosomal dominant disorder. The present report represents the ninth reported case and only the second case involving a female. She had a characteristic pattern of limb anomalies including agenesis of the tibiae and bilateral preaxial polydactyly of the feet, associated with genital hypoplasia.