Louise Lapagesse de Camargo Pinto

Mucopolysaccharidoses in Brazil: what happens from birth to biochemical diagnosis?

Mucopolysaccharidoses (MPS) form a group of inherited metabolic disorders characterized by intralysosomal storage of glycosaminoglycans. This study aimed to investigate the path followed by Brazilian patients from birth to diagnosis. An interview was conducted with patients parents or guardians with subsequent review of patients medical records. One hundred thirteen patients with MPS were included (MPS I: 18, MPS II: 43, MPS IIIA: 2, MPS IIIB: 3, MPS IIIC: 1, MPS IVA: 15, MPS IVB: 1, MPS VI: 29, MPS VII: 1) from 97 families. Median age at the onset of signs/symptoms was 18 months (MPS I: 18, MPS II: 24, MPS IVA: 8, MPS VI: 8). Skeletal abnormalities (for MPS IVA and MPS VI), joint contractures (for MPS II), and typical facial features (for MPS I) were the most frequently reported first signs/symptoms. Several health professionals were involved in patients care as of the onset of symptoms until biochemical diagnosis was established. Median age at diagnosis was 76 months (MPS I: 75, MPS II: 95, MPS IVA: 75, MPS VI: 52). Considering the group as a whole, there was a 4.8‐year delay between the onset of signs/symptoms and the establishment of the diagnosis. Considering that specific therapies are available for some of these disorders and that early treatment is likely to change more favorably the natural history of the disease, efforts should be made to minimize this delay. We believe that this situation can be improved by measures that both increase awareness of health professionals about MPS and improve access to diagnostic tests.

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.

Orthopedic manifestations in patients with muco­polysaccharidosis type II (Hunter syndrome) enrolled in the Hunter Outcome Survey

Mucopolysaccharidosis type II (MPS II or Hunter syndrome) is a rare, inherited disorder caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase. As a result of this deficiency, glycosaminoglycans accumulate in lysosomes in many tissues, leading to progressive multisystemic disease. The cardiopulmonary and neurological problems associated with MPS II have received considerable attention. Orthopedic manifestations are common but not as well characterized. This study aimed to characterize the prevalence and severity of orthopedic manifestations of MPS II and to determine the relationship of these signs and symptoms with cardiovascular, pulmonary and central nervous system involvement. Orthopedic manifestations of MPS II were studied using cross-sectional data from the Hunter Outcome Survey (HOS). The HOS is a global, physician-led, multicenter observational database that collects information on the natural history of MPS II and the long-term safety and effectiveness of enzyme replacement therapy. As of January 2009, the HOS contained baseline data on joint range of motion in 124 males with MPS II. In total, 79% of patients had skeletal manifestations (median onset, 3.5 years) and 25% had abnormal gait (median onset, 5.4 years). Joint range of motion was restricted for all joints assessed (elbow, shoulder, hip, knee and ankle). Extension was the most severely affected movement: the exception to this was the shoulder. Surgery for orthopedic problems was rare. The presence of orthopedic manifestations was associated with the presence of central nervous system and pulmonary involvement, but not so clearly with cardiovascular involvement. Orthopedic interventions should be considered on an individual-patient basis. Although some orthopedic manifestations associated with MPS II may be managed routinely, a good knowledge of other concurrent organ system involvement is essential. A multidisciplinary approach is required.

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.

Avaliação prospectiva de 11 pacientes brasileiros com mucopolissacaridose II

OBJETIVO: Avaliar a progressao da mucopolissacaridose II, durante um periodo de 12 meses, em 11 pacientes brasileiros. METODOS: Onze pacientes brasileiros com mucopolissacaridose II foram avaliados prospectivamente no Servico de Genetica Medica do Hospital de Clinicas de Porto Alegre. As avaliacoes realizadas na visita inicial e na de 12 meses foram: anamnese, exame fisico, ressonância nuclear magnetica abdominal, ecocardiograma, teste da caminhada em 6 minutos, audiometria, exames bioquimicos sericos e dosagem urina- ria de glicosaminoglicanos. RESULTADOS: Os principais achados relativos a comparacao entre as duas visitas foram: 1) dois pacientes apresentaram retardo de crescimento; 2) dois pacientes apresentaram variacao negativa em relacao ao peso; 3) um paciente apresentou variacao de obesidade para sobrepeso; 4) tres pacientes desenvolveram alargamento do ventriculo esquerdo; destes, dois aumentaram o numero de lesoes nas valvas cardiacas; 5) nao foi encontrada diferenca estatistica significativa entre a media das distâncias percorridas no teste da caminhada em 6 minutos; 6) houve aumento do volume esplenico; 7) ocorreu aumento dos niveis de gamaglutamiltransferase; 8) nao houve alteracao dos niveis urinarios de glicosaminoglicanos. CONCLUSOES: De uma maneira geral, a unica variavel que apresentou, no periodo estudado, piora com potencial repercussao clinica imediata foram os achados ecocardiograficos. Embora o periodo de 12 meses seja curto para medir alteracoes na maioria dos parâmetros comprometidos na mucopolissacaridose II, sua natureza progressiva deve ser levada em conta na avaliacao da eficacia dos protocolos de tratamento para essa condicao.

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.

Are MPS II heterozygotes actually asymptomatic? A study based on clinical and biochemical data, x-inactivation analysis and imaging evaluations

For some X‐linked disorders the expressivity and penetrance in females are almost similar to those ones found in males. For mucopolysaccharidosis type II (MPS II), there are no studies in the literature trying to identify subtle signs and symptoms of this disease in heterozygotes. The objective of this study was to compare heterozygotes and non‐heterozygotes for MPS II, in order to test the hypothesis that heterozygotes may present subtle manifestations of the disease. In this observational and transversal study we collected data on 40 Brazilian women with a positive familial history for MPS II that included clinical and physical exam, karyotype, pattern of X‐inactivation, iduronate‐2‐sulfatase (IDS) activity in leukocytes and plasma, urinary glycosaminoglycans levels, computerized tomography scans (CT) of abdomen and spine, and brain magnetic resonance imaging. The Results showed the following: According to DNA analysis, 22 women were classified as heterozygote and 18 as non‐heterozygotes. We did not find any abnormality on physical examination, karyotype, or spine CT. Also the pattern of X‐inactivation was not different between the groups. Applying the Bonferronis correction, both groups were found to differ only in relation to IDS activity in plasma and in leukocyte, which were lower in heterozygotes. In our investigation we did not find any evidence of subtle clinical manifestations of MPS II in heterozygotes. Our findings suggest there is no relation between the absence of clinical signs in these women and the occurrence of a favorable skewing pattern of X‐inactivation.

Use of a multiplex ligation-dependent probe amplification method for the detection of deletions/duplications in the GBA1 gene in Gaucher disease patients

Gaucher disease (GD) is caused by the deficient activity of β-glucocerebrosidase due to pathogenic mutations in the GBA1. This gene has a pseudogene (GBAP) with 96% of sequence homology. Recombination (Rec) events in the GBA1 seem to be facilitated by an increased degree of homology and proximity to the GBAP. The objectives of this study were to validate the P338-X1 GBA kit (MRC-Holland) for Multiplex Ligation-dependent Probe Amplification (MLPA) and to detect larger deletions/duplications present in GBA1 in GD patients from Brazil. Thirty-three unrelated Brazilian GD patients, previously genotyped by the Sanger method (both pathogenic alleles identified=29 patients, only one allele identified=3 patients, no pathogenic alleles identified=1 patient), were evaluated by the MLPA assay. MLPA was compatible with the previous results obtained by Sanger sequencing and identified an additional allele (a heterozygous deletion in intron 7 in one patient with only one mutation identified by Sanger). Our data suggest that, although larger deletions/duplications do not appear to be frequent in GD, the P338-X1 GBA kit for MLPA appears to be a good method for GBA1 analysis. Additional investigations should be performed in order to characterize the remaining four uncharacterized alleles of our sample.

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

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