Maria Raquel Santos Carvalho

Variations in genotype-phenotype correlations in phenylketonuria patients.

Phenylalanine hydroxylase deficiency is a trait inherited in an autosomal recessive pattern; the associated phenotype varies considerably. This variation is mainly due to the considerable allelic heterogeneity in the phenylalanine hydroxylase enzyme locus. We examined the genotype-phenotype correlation in 54 phenylketonuria (PKU) patients from Minas Gerais, Brazil. Two systems were used. The first was a phenotype prediction system based on arbitrary values (AV) attributed to each mutation and the second was a correlation analysis. An AV was assigned to each mutation: AV = 1 for classical PKU mutation; AV = 2 for moderate PKU mutation; AV = 4 for mild PKU mutation, and AV = 8 for non-PKU hyperphenylalaninemia mutation. The observed phenotype for AV analysis was the clinical diagnosis established by the overloading phenylalanine test. Among the 51 PKU patients that we analyzed based on this trait, in 51% the predicted phenotype did not match the observed phenotype; the highest degree of concordance was found in patients with null/null genotypes. The genotype was observed to be a good predictor of the clinical course of the patients and significant correlations were found between phenylalanine values at first interview and predicted residual activity, genotype and arbitrary value sum.

Effect of ACTN3 gene on strength and endurance in soccer players.

Abstract Pimenta, EM, Coelho, DB, Veneroso, CE, Barros Coelho, EJ, Cruz, IR, Morandi, RF, De A. Pussieldi, G, Carvalho, MRS, Garcia, ES, and De Paz Fernández, JA. Effect of ACTN3 gene on strength and endurance in soccer players. J Strength Cond Res 27(12): 3286–3292, 2013—Sports efficiency in activities in which strength and speed are the determining factors has been associated to the ACTN3 gene, which is responsible for the expression of &agr;-actinin-3. Soccer is a mainly aerobic sport because of its long duration, but the acute actions that define the game demand a lot of strength and speed. The purpose of the present study was to compare the performance capacity of soccer players with different genotype groups of ACTN3 (XX, RX, and RR) in strength, speed, and endurance tests. Two hundred professional players of Brazilian soccer first division teams participated in this study. Speed, jump, and endurance test results were compared with the polymorphisms of the ACTN3 gene. It was noticed that RR individuals spent less time to run a 10-m path, compared with XX individuals (p < 0.05). The RR individuals also presented lower time rates at the 20- and 30-m path, compared with RX and XX individuals (p < 0.05). In jump tests, RR individuals presented higher rates, compared with RX and XX individuals (p < 0.05). As for aerobic tests, the XX individuals presented higher rates of V[Combining Dot Above]O2 max, compared with the RR group (p < 0.05), and did not differ from the RX group. The main conclusion of this study is that soccer players of genotype ACTN3/RR are the fastest in short distances and present higher jump potential. ACTN3/XX individuals presented the highest aerobic capacity. These findings can be used in training load adjustment and can influence the development of tactical schemes in soccer matches.

Validação da Bateria de Avaliação da Memória de Trabalho (BAMT-UFMG)

Working memory may be conceived in terms of storing systems or by means of models of dynamic processes. We adapted a working memory assessment procedure based on a process model for use in Brazil. The model conceives working memory as three interrelated aspects: processing speed or efficiency, temporary storage and coordinative capacity. Results with 832 participants of several ages and educational levels indicate that the procedure is adequate to be used in our cultural environment, preserving the original characteristics and displaying acceptable reliability and validity characteristics. Working memory performance correlated with measures of executive function and fluid intelligence but not with measures of associative episodic memory. This research program will be pursued further examining the clinical neuropsychological usefulness of the BAMT-UFMG.

Mutational analysis of two boys with the severe perinatally lethal Melnick–Needles syndrome†

Melnick–Needles syndrome (MNS) (OMIM 309350) is a rare, X‐linked dominant condition, caused by mutations in the filamin A gene (FLNA, on Xq28). In females, the syndrome presents with bone dysplasia and characteristic facial changes. Affected males may show two different phenotypes. One is similar to the female phenotype and is seen in children born to unaffected mothers and suggesting new mutations. Alternatively, males born to affected mothers have an embryonic or perinatally lethal disorder. It has been claimed that MNS constitutes part of a spectrum including frontometaphyseal dysplasia, otopalatodigital syndrome type 1 (OPD1) and otopalatodigital syndrome type 2 (OPD2). These conditions are produced by different mutations in the filamin A gene (FLNA). MNS is caused by three different mutations in FLNA exon 22, to date detected only in females. We describe the clinical manifestations and present the results of FLNA exon 22 mutations screening in two boys with the perinatally lethal form of MNS and their affected mothers. In order to obtain DNA amplification from paraffin‐embedded tissues, we designed a new method based on hemi‐nested PCR. One of the children (and his mother) had a previously undescribed mutation produced by a double SNP in the positions 3776 and 3777 of the gene and leading to an amino acid substitution (NP_001447:p.[Gly1176Asp]). The second child (and his mother) had an already known mutation (NP_001447.2:p[.Ser1199Leu]). This is the first report confirming the presence FLNA mutations in boys with the perinatally lethal phenotype of MNS.

Count on dopamine: influences of COMT polymorphisms on numerical cognition

Catechol-O-methyltransferase (COMT) is an enzyme that is particularly important for the metabolism of dopamine. Functional polymorphisms of COMT have been implicated in working memory and numerical cognition. This is an exploratory study that aims at investigating associations between COMT polymorphisms, working memory, and numerical cognition. Elementary school children from 2th to 6th grades were divided into two groups according to their COMT val158met polymorphism [homozygous for valine allele (n = 61) vs. heterozygous plus methionine homozygous children or met+ group (n = 94)]. Both groups were matched for age and intelligence. Working memory was assessed through digit span and Corsi blocks. Symbolic numerical processing was assessed through transcoding and single-digit word problem tasks. Non-symbolic magnitude comparison and estimation tasks were used to assess number sense. Between-group differences were found in symbolic and non-symbolic numerical tasks, but not in working memory tasks. Children in the met+ group showed better performance in all numerical tasks while val homozygous children presented slower development of non-symbolic magnitude representations. These results suggest COMT-related dopaminergic modulation may be related not only to working memory, as found in previous studies, but also to the development of magnitude processing and magnitude representations.

PKU in Minas Gerais State, Brazil: Mutation Analysis

This work was undertaken in order to ascertain the PKU mutational spectrum in Minas Gerais, Brazil, the relative frequency of the mutations in the State and the origin of these mutations by haplotype determination. Minas Gerais is a trihybrid population formed by miscegenation from Europeans, Africans and Amerindians. All 13 exons of the PAH gene from 78 PKU patients were analyzed, including splicing sites and the promoter region. We identified 30 different mutations and 98% of the PAH alleles were established. A new mutation (Q267X) was identified as well. The most common mutations found were V388M (21.2), R261Q (16.0%), IVS10‐11G>A (15.3%), I65T (5.8%), IVS2+5G>C (5.8%), R252W (5.1%), IVS2+5G>A (4.5%), P281L (3.8%) and L348V (3.2%). These nine mutations correspond to 80% of the PKU alleles in the state. Haplotypes were determined to characterize the origin of the PAH alleles. The majority of the mutations found, with respective haplotypes, are frequent in the Iberian Peninsula. However, there were some mutations that are rare in Europe and four previously unreported mutation‐haplotype associations. I65T and Q267X were found in association with haplotype 38 and may be African in origin or the result of miscegenation in the Brazilian population.

Genetic diversity and population structure in Brazilian Mangalarga Marchador horses.

One hundred and fifteen unrelated Mangalarga Marchador horses were sampled from three geographically distinct regions of Minas Gerais State, Brazil (South, Southeast, and Northeast) and tested for 10 microsatellite loci. Genetic diversity and population structure parameters were estimated with ARLEQUIN 3.0, CERVUS 2.0, POPGENE 1.31, GENEPOP on the web, STRUCTURE 2.0, and SPAGEDI 1.2 software packages. Under Hardy-Weinberg assumptions, seven markers were at equilibrium (LEX014, LEX017, LEX019, SGCV23, TKY321, VHL20, and VIASH39), while two (ASB3 and LEX031) presented significant homozygote excess. Seventy-four alleles were identified in these nine markers, with a mean of 8.22 alleles. Mean heterozygosity was 0.637 and polymorphism information content was 0.662. Markers ASB3, LEX019, SGCV23, TKY321, and VHL20 were highly informative (PIC >0.7) and may be useful for eventual expansion of parentage test panels. The F(ST) value (0.0562) indicated relatively little geographical structure. However, based on a Bayesian-based cluster analysis under a three-cluster model, 94% of the 115 individuals were correctly assigned to the subpopulations from where they were sampled. Mean pairwise f was relatively high (0.11), and in spite of the efforts towards non-consanguineous sampling, 1% of the pairs of individuals shared over 50% of the alleles. These results strongly suggest that the population is genetically structured. Under a conservation genetics approach, two strategies are recommended: avoidance of crosses between highly endogamic individuals and stimulation of crosses between individuals from those regions for which low genetic flow was identified.

Are 22q11.2 distal deletions associated with math difficulties

Approximately 6% of school‐aged children have math difficulties (MD). A neurogenetic etiology has been suggested due to the presence of MD in some genetic syndromes such as 22q11.2DS. However, the contribution of 22q11.2DS to the MD phenotype has not yet been investigated. This is the first population‐based study measuring the frequency of 22q11.2DS among school children with MD. Children (1,564) were identified in the schools through a screening test for language and math. Of these children, 152 (82 with MD and 70 controls) were selected for intelligence, general neuropsychological, and math cognitive assessments and for 22q11.2 microdeletion screening using MLPA. One child in the MD group had a 22q11.2 deletion spanning the LCR22‐4 to LCR22‐5 interval. This child was an 11‐year‐old girl with subtle anomalies, normal intelligence, MD attributable to number sense deficit, and difficulties in social interactions. Only 19 patients have been reported with this deletion. Upon reviewing these reports, we were able to characterize a new syndrome, 22q11.2 DS (LCR22‐4 to LCR22‐5), characterized by prematurity; pre‐ and postnatal growth restriction; apparent hypotelorism, short/upslanting palpebral fissures; hypoplastic nasal alae; pointed chin and nose; posteriorly rotated ears; congenital heart defects; skeletal abnormalities; developmental delay, particularly compromising the speech; learning disability (including MD, in one child); intellectual disability; and behavioral problems. These results suggest that 22q11.2 DS (LCR22‐4 to LCR22‐5) may be one of the genetic causes of MD.

PERMANENT GENETIC RESOURCES: Characterization of eight microsatellite loci in the woolly mouse opossum, Micoureus paraguayanus, isolated from Micoureus demerarae

Eight novel microsatellite markers were isolated from the woolly mouse opossum from the Amazon Forest in Peru, Micoureus demerarae, using a partial genomic DNA library and an enrichment protocol. These loci were polymorphic in M. demerarae and Micoureus paraguayanus populations from the Atlantic Forest in Brazil with the number of alleles ranging from two to 23. Those eight loci plus another five already described for M. paraguayanus will allow for the evaluation of genetic diversity of populations from the ‘Rio Doce’ Park, one of the last Atlantic Forest fragments in Minas Gerais state, Brazil.

Influence of Arg72Pro polymorphisms of TP53 on the response of buccal cells to radiotherapy.

Polymorphisms in the TP53 gene codon 72 (Arg72Pro) influence apoptosis induction and DNA damage repair. We evaluated how variants of protein p53 (p53Arg and p53Pro) affect cell death and DNA damage repair by analyzing the frequencies of karyorrhexis and micronuclei. There were significant differences in the frequency of karyorrhexis between the three p53 genotypes (Arg/Arg, Arg/Pro, and Pro/Pro), between samples taken before and after radiotherapy, and between patients and controls. The frequency of micronucleated cells increased significantly after radiotherapy. There were no significant differences in the micronucleus frequency in healthy tissues of these patients compared to controls, or in the comparisons between the three genotypes. We conclude that Arg72Pro polymorphism influences cell apoptotic capacity. This is the first study investigating karyorrhexis and micronuclei, as indicators of apoptosis after radiotherapy, and how these indicators are influenced by the TP53 polymorphism Arg72Pro.