Elevation of glycosaminoglycans in the amniotic fluid of a fetus with mucopolysaccharidosis VII

OBJECTIVE

The aim of this study was to quantify glycosaminoglycans (GAGs) in amniotic fluid (AF) from an MPS VII fetus compared with age-matched fetuses obtained from normal pregnancies.

METHOD

Disaccharides were measured by liquid chromatography tandem mass spectrometry, compared to age-matched controls. Enzyme assay was performed in AF supernatant or cultured amniocytes. GUSB was analyzed by next generation sequencing using Ion Torrent Personal Genome Machine with a customized panel.

RESULTS

No activity of β-glucuronidase was detected in fetal cells. The pregnancy was spontaneously terminated in the third trimester. Genetic studies identified a homozygous mutation of p.N379D (c.1135A > G) in the GUSB gene. Liquid chromatography tandem mass spectrometry showed that chondroitin sulfate, dermatan sulfate, heparan sulfate, and keratan sulfate levels were markedly increased in the MPS VII AF, compared to those in age-matched control AF (dermatan sulfate, heparan sulfate, and chondroitin-6-sulfate more than 10 × than age-matched controls; chondroitin-4-sulfate and keratan sulfate more than 3 times higher).

CONCLUSION

This is the first report of specific GAG analysis in AF from an MPS VII fetus, indicating that GAG elevation in AF occurs by 21 weeks of gestation and could be an additional tool for prenatal diagnosis of MPS VII and potentially other MPS types. © 2017 John Wiley & Sons, Ltd.

Pitfalls in the prenatal diagnosis of mucolipidosis II alpha/beta: A case report

Mucolipidosis II alpha/beta is an autosomal recessive disorder caused by deficient activity of GlcNAc-1-phosphotransferase. We report the prenatal diagnosis of a fetus who was found to exhibit normal levels of lysosomal enzymes in the amniotic fluid but low levels in amniocytes, and who was found to be heterozygous for the most common GNPTAB mutation. As in some carriers of Mucolipidosis II biochemical abnormalities may hinder prenatal diagnosis, we suggest DNA analysis should be performed whenever possible.

Chromosome analysis in 31 cases of benign and malignant breast tumors: a study in Brazil

Cultures of 31 breast tumors, being 20 carcinomas and 11 benign lesions, were cytogenetically analysed. Clonal chromosome aberrations were detected in 16 carcinomas and in 4 benign lesions. Nine carcinomas and 2 benign lesions had multiple cytogenetically unrelated and related clones, whereas a single abnormal clone was observed in 7 carcinomas and in 2 benign lesions. Polyploid clones were found in 7 carcinomas and in 2 benign lesions. The presence of clonal chromosome aberrations and polyploid cells was not associated with the clinicopathologic parameters tested. Carcinomas had more clonal changes than benign lesions (p = 0.031), showing that cytogenetic features are of diagnostic value and that different chromosome anomalies might have different pathogenetic and prognostic significance.

[Alpha-fetoprotein: normal values in amniotic fluid between 14 and 21 weeks]

BACKGROUND

To define the normal values of amniotic fluid alphafetoprotein in pregnant women, whose gestational ages range from 14 to 21 weeks, in the Hospital de Clínicas de Porto Alegre.

MATERIAL AND METHOD

One hundred thirty seven women with indication for amniocentesis were studied. The alphafetoprotein was measured in all samples using enzyme immunoassay. One hundred and nine normal pregnancies were selected. All of these fetuses had normal karyotype and had no malformation. They were not twins and their amniotic fluid samples were not bloody. These samples were divided by their gestational ages. Then the medians of the alphafetoprotein values and their multiples were calculated.

RESULTS

The medians of alphafetoprotein (KUI/ml) for each gestational age were as follows: 14 weeks: 16.32; 15 weeks: 14.36; 16 weeks: 13.43; 17 weeks: 10.93; 18 weeks: 8.22; 19 weeks: 7.35; 20 weeks: 5.62; 21 weeks: 4.47.

CONCLUSION

The establishment of alphafetoprotein normal values in our service allows us to use this assay for patients at risk of neural tube defects. It also makes possible to analyze samples sent for cytogenetic or metabolic studies, in order to identify elevated levels of alphafetoprotein, so that these fetuses could have a more detailed sonography study to look for malformations.