Beta-mannosidosis: prenatal detection of caprine allantoic fluid oligosaccharides with thin layer, gel permeation and high performance liquid chromatography

Development and efficacy of ultrasound-guided fetal fluid aspiration techniques for prenatal diagnosis of caprine β-mannosidosis

Ultrasound-guided fetal fluid sampling was performed on 13 pregnant goats at Days 59 to 65 of gestation to establish safe techniques for accurate sampling and to determine the feasibility of prenatal diagnosis of beta-mannosidosis. Fluids were analyzed for electrolyte and creatinine content to assess accuracy of sampling. Values correlated well with previously reported concentrations for caprine and ovine fetal fluids at the same gestational stage. The single abortion which occurred following ultrasound-guided sampling was correlated with placentome penetration and aspiration of bloody fluids. Thin layer chromatography of amniotic and allantoic fluids was performed to detect oligosaccharides that accumulate in beta-mannosidosis. Abnormal accumulated oligosaccharides were identified in the allantoic but not amniotic fluid from a beta-mannosidase-deficient 62-d-old fetus. Thus, allantocentesis was shown to be an optimal, safe procedure for providing information at this gestational stage to diagnose caprine beta-mannosidosis.

Mammalian beta-D-mannosidase and beta-mannosidosis

Lysosomal beta-D-mannosidase is the last exoglycosidase involved in the sequential degradation of the N-glycosylproteins glycans. Research on this enzyme was restricted before the discovery of its hereditary deficiency, first in goat (1981) and later in man (1986). We describe the biochemical aspects of these beta-mannosidosis and the properties of the beta-mannosidases of mammalian origin. Our own results concerning human enzyme (from kidney and urine, seminal plasma and blood cells) suggest that, apart from the case of the inherited disease, beta-mannosidase may become a useful tool in other pathologies.

Application of lectin histochemistry and carbohydrate analysis to the characterization of lysosomal storage diseases

In lysosomal storage diseases that involve a defect in the catabolism of glycoconjugates, lectin histochemistry adds a new dimension to the characterization of stored carbohydrates as it identifies sugar residues in situ in the affected cells and, thus, determines which cell types are affected by storage. It may be combined with chemical and biochemical analysis by h.p.l.c. The present review summarizes recent results for a variety of storage diseases and presents new data for GM1-gangliosidosis.

Regional central nervous system oligosaccharide storage in caprine beta-mannosidosis

Goats affected with beta-mannosidosis, an autosomal recessive disease of glycoprotein metabolism, have deficient activity of the lysosomal enzyme beta-mannosidase along with tissue storage of oligosaccharides, including a trisaccharide [Man(beta 1-4)GlcNAc(beta 1-4)GlcNAc] and a disaccharide [Man(beta 1-4)GlcNAc]. CNS myelin deficiency, with regional variation in severity, is a major pathological characteristic of affected goats. This study was designed to investigate regional CNS differences in oligosaccharide accumulation to assess the extent of correlation between oligosaccharide accumulation and severity of myelin deficits. The concentrations of accumulated disaccharide and trisaccharide and the activity of beta-mannosidase were determined in cerebral hemisphere gray and white matter and in spinal cord from three affected and two control neonatal goats. In affected goats, the content of trisaccharide and disaccharide in spinal cord (moderate myelin deficiency) was similar to or greater than that in cerebral hemispheres (severe myelin deficiency). Thus, greater oligosaccharide accumulation was not associated with more severe myelin deficiency. Regional beta-mannosidase activity levels in control goats were consistent with the affected goat oligosaccharide accumulation pattern. The similarity of trisaccharide and disaccharide content in cerebral hemisphere gray and white matter suggested that lysosomal storage vacuoles, more numerous in gray matter, may not be the only location of stored CNS oligosaccharides.