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. METHODS: This observational, multicenter study used a convenience sampling strategy, with sequencing of exons 2, 3, and 4 of the BTD gene. RESULTS: The sample comprised 38 individuals with biochemical phenotypes defined a priori on the basis of biotinidase activity in serum/plasma (2 with profound deficiency, 9 with partial deficiency, 15 heterozygous, 1 borderline between partial deficiency and heterozygosity, 2 borderline between heterozygous and normal) or dried blood spot sample (n = 9, all with unspecified deficiency). Most patients were from Southern Brazil (n = 29/38) and were identified by neonatal screening (n = 33/38). Parental consanguinity was reported in two cases. The most commonly found genetic variants were c.1330G > C (p.D444H), c.755A > G (p.D252G), and c.[511G > A;1330G > C] (p.[A171T;D444H]), with allele frequencies of 50%, 9.4%, and 5.4% respectively. Three novel pathogenic variants were identified (c.119 T > C or p.L40P, c.479G > A or p.C160Y, and c.664G > A or p.D222N). Twenty-nine patients had two pathogenic variants detected (with cis/trans status ascertained in 26/29), six had only one variant, and three had no pathogenic variants detected. Genotyping confirmed the original phenotypic classification based on enzyme activity in 16/26 cases. Three polymorphic variants were identified in control individuals, of which two were nonpathogenic (c.1171C > T or p.P391S and c.1413 T > C or p.C471C, with a frequency of 1.5% and 5.5% respectively) and one pathogenic (c.1330G > C, frequency 4%). CONCLUSIONS: Our findings suggest that partial BD is the most common form of BD in Brazil, and expand current knowledge on the allelic heterogeneity of this condition.

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

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

Prospective study of 11 Brazilian patients with mucopolysaccharidosis II.

OBJECTIVE: To assess the progression of mucopolysaccharidosis II in 11 Brazilian patients over a 12-month period. METHODS: Eleven Brazilian patients with mucopolysaccharidosis II were prospectively studied at the Division of Medical Genetics of Hospital de Clínicas de Porto Alegre. The initial assessment and the assessment at 12 months included: anamnesis, physical examination, abdominal nuclear magnetic resonance, echocardiogram, 6-minute walk test, audiometry, serum biochemical tests and urinary glycosaminoglycan concentration. RESULTS: The major findings after comparing the assessments were: 1) two patients had growth retardation; 2) two patients showed negative weight change; 3) one patient went from obese to overweight; 4) three patients revealed left ventricle hypertrophy; of these, two increased the number of cardiac valve lesions; 5) there was no statistically significant difference between the mean distances obtained on the 6-minute walk test; 6) there was splenic enlargement; 7) there was an increase in gamma-glutamyltransferase levels; 8) the urinary concentration of glycosaminoglycans remained unchanged. CONCLUSIONS: In general, echocardiographic findings were the only variable with deterioration and possible immediate clinical consequences. Although a 12-month period is too short to detect changes in most variables related to mucopolysaccharidosis II, its progressive nature should be taken into account when evaluating the efficiency of treatment protocols.

[Report of a Brazilian patient with Wolfram Syndrome]. / Relato de um paciente brasileiro com síndrome de Wolfram.

OBJECTIVE: To report a case of a patient diagnosed with Wolfram Syndrome and brachydactyly type E. Wolfram Syndrome is characterized by the presence of diabetes mellitus, diabetes insipidus, atrophy of the optic nerve, alterations of the urinary tract, deafness and neurologic and psychiatric disorders. However, not all manifestations are present at diagnosis, indicating the necessity of long-term follow-up of these patients. This long-term follow-up should be extended to the patients' closest relatives, having in mind the increased risk of occurrence of psychiatric disorders and diabetes mellitus among the heterozygous carriers of Wolfram Syndrome. DESCRIPTION: Male, white patients, only child of non-consanguineous parents, was healthy until four years of age, when he presented with polydipsia and polyuria, being diagnosed with diabetes mellitus type I. Since then, he has needed regular insulin use, but has followed an inadequate diet due to socioeconomic problems. He was evaluated by the genetic service when he was 11 years old. Brachydactyly was observed on physical examination. In the course of the complementary investigation, bilateral atrophy of the optic nerve was observed; the visual evoked potential and the electroretinogram were compatible with extensive optic nerve injury. Both retinas were normal. The presence of insulin-dependent diabetes mellitus together with atrophy of the optic nerve is a sufficient criterion for the diagnosis of Wolfram Syndrome. The molecular investigation confirmed the diagnosis of Wolfram Syndrome. COMMENTS: The aim of the present report is to alert physicians about the association between diabetes mellitus and monogenic syndromes, such as Wolfram Syndrome.

Expression of the disease on female carriers of X-linked lysosomal disorders: a brief review.

Most lysosomal diseases (LD) are inherited as autosomal recessive traits, but two important conditions have X-linked inheritance: Fabry disease and Mucopolysaccharidosis II (MPS II). These two diseases show a very different pattern regarding expression on heterozygotes, which does not seem to be explained by the X-inactivation mechanism only. While MPS II heterozygotes are asymptomatic in most instances, in Fabry disease most of female carriers show some disease manifestation, which is sometimes severe. It is known that there is a major difference among X-linked diseases depending on the cell autonomy of the gene product involved and, therefore, on the occurrence of cross-correction. Since lysosomal enzymes are usually secreted and uptaken by neighbor cells, the different findings between MPS II and Fabry disease heterozygotes can also be due to different efficiency of cross-correction (higher in MPS II and lower in Fabry disease). In this paper, we review these two X-linked LD in order to discuss the mechanisms that could explain the different rates of penetrance and expressivity observed in the heterozygotes; this could be helpful to better understand the expression of X-linked traits.

Esophageal stenosis in a child presenting a de novo 7q terminal deletion.

We report on the first case of a child with a de novo 7q terminal deletion [46,XX,del(7)(q35 → qter)] presenting esophageal stenosis. This cytogenetic abnormality was confirmed by FISH, using subtelomeric probes, and by a whole-genome array-CGH assay. The child also had phenotypic features previously described in patients with a similar deletion, as growth retardation, microcephaly, coloboma of papilla, ptosis, hearing loss, urinary tract anomalies, partial agenesis of sacrum, hypotonia and neuropsychomotor delay. The odontoid hypoplasia identified, in similarity with the esophageal stenosis, represents an uncommon finding. This report is also the first clinical description of a patient with an abnormality involving the sonic hedgehog gene and an esophageal alteration. It is discussed the possibility of a specific association between them, according to some results observed in studies with animal models.

Prospective study of 11 Brazilian patients with mucopolysaccharidosis II

OBJETIVO: Avaliar a progressão da mucopolissacaridose II, durante um período de 12 meses, em 11 pacientes brasileiros. MÉTODOS: Onze pacientes brasileiros com mucopolissacaridose II foram avaliados prospectivamente no Serviço de Genética Médica do Hospital de Clínicas de Porto Alegre. As avaliações realizadas na visita inicial e na de 12 meses foram: anamnese, exame físico, ressonância nuclear magnética abdominal, ecocardiograma, teste da caminhada em 6 minutos, audiometria, exames bioquímicos séricos e dosagem uriná- ria de glicosaminoglicanos. RESULTADOS: Os principais achados relativos à comparação entre as duas visitas foram: 1) dois pacientes apresentaram retardo de crescimento; 2) dois pacientes apresentaram variação negativa em relação ao peso; 3) um paciente apresentou variação de obesidade para sobrepeso; 4) três pacientes desenvolveram alargamento do ventrículo esquerdo; destes, dois aumentaram o número de lesões nas valvas cardíacas; 5) não foi encontrada diferença estatística significativa entre a média das distâncias percorridas no teste da caminhada em 6 minutos; 6) houve aumento do volume esplênico; 7) ocorreu aumento dos níveis de gamaglutamiltransferase; 8) não houve alteração dos níveis urinários de glicosaminoglicanos. CONCLUSÕES: De uma maneira geral, a única variável que apresentou, no período estudado, piora com potencial repercussão clínica imediata foram os achados ecocardiográficos. Embora o período de 12 meses seja curto para medir alterações na maioria dos parâmetros comprometidos na mucopolissacaridose II, sua natureza progressiva deve ser levada em conta na avaliação da eficácia dos protocolos de tratamento para essa condição.

OBJECTIVE: To assess the progression of mucopolysaccharidosis II in 11 Brazilian patients over a 12-month period. METHODS: Eleven Brazilian patients with mucopolysaccharidosis II were prospectively studied at the Division of Medical Genetics of Hospital de Clínicas de Porto Alegre. The initial assessment and the assessment at 12 months included: anamnesis, physical examination, abdominal nuclear magnetic resonance, echocardiogram, 6-minute walk test, audiometry, serum biochemical tests and urinary glycosaminoglycan concentration. RESULTS: The major findings after comparing the assessments were: 1) two patients had growth retardation; 2) two patients showed negative weight change; 3) one patient went from obese to overweight; 4) three patients revealed left ventricle hypertrophy; of these, two increased the number of cardiac valve lesions; 5) there was no statistically significant difference between the mean distances obtained on the 6-minute walk test; 6) there was splenic enlargement; 7) there was an increase in gamma-glutamyltransferase levels; 8) the urinary concentration of glycosaminoglycans remained unchanged. CONCLUSIONS: In general, echocardiographic findings were the only variable with deterioration and possible immediate clinical consequences. Although a 12-month period is too short to detect changes in most variables related to mucopolysaccharidosis II, its progressive nature should be taken into account when evaluating the efficiency of treatment protocols.

Relato de um paciente brasileiro com síndrome de Wolfram / Report of a Brazilian patient with Wolfram Syndrome

Objetivos: relatar o caso de um paciente com diagnóstico de sindrome de Wolfram (SW) e braquidactilia do tipo E. A sindrome de Wolfram é caracterizada pela presença de diabetes melito, diabetes insipido, atrofia do nervo óptico, alterações do trato urinário, surdez e distúrbios neurológicos e psiquiátricos. No entanto, nem todas as manifestações estarão presentes no momento do diagnósti-co, indicando a necessidade de acompanhamento a longo prazo destes pacientes. Este acompanhamento deve ser estendido aos familiares diretos, tendo em vista o risco aumentado da ocorrência de distúrbios psiquiátricos e diabetes melito entre os portadores heterozigotos da sindrome de Wolfram. Descrição: menino, branco, filho de pais não consanguineos, era rigido até os 4 anos, quando iniciou com polidipsia e poliúria, sendo diagnosticada diabetes melito tipo I. Desde entÒo, faz uso irregular de insulina e segue mal a dieta por problemas socioeconômicos. Foi avaliado pelo serviço de GenÚtica aos 11 anos de idade. Ao exame fisico, chamou a atenção a presença de braquidactilia. Durante a investigação complementar, constatou-se atrofia bilateral do nervo óptico, com potencial evocado visual e eletrorretinograma compatíveis com lesão grave de nervo. Ambas retinas eram normais. A presença de diabetes melito insulino-dependente e atrofia do nervo óptico são critérios suficientes para o diagnóstico de síndrome de Wolfram. A investigação molecular confirmou o diagnóstico. Comentários: o presente relato tem o objetivo de alertar os profissionais da area médica para a associação entre o diabetes melito e síndromes monogênicas, como a SW