Multiple Sulphatase Deficiency Research Articles

How many sulphatase deficiencies become multiple? The diagnostic challenges of multiple sulphatase deficiency

How many sulphatase deficiencies become multiple? The diagnostic challenges of multiple sulphatase deficiency

How many sulphatase deficiencies become multiple: An unusual presentation of multiple sulphatase deficiency

How many sulphatase deficiencies become multiple: An unusual presentation of multiple sulphatase deficiency

Sulfatase activities are regulated by the interaction of the sulfatase-modifying factor 1 with SUMF2.

Sulphatases undergo a unique post-translational modification that converts a highly conserved cysteine located within their active site into formylglycine. This modification is necessary for the catalytic activities of the sulphatases, and it is generated by the protein product of sulphatase-modifying factor 1 (SUMF1), the gene mutated in multiple sulphatase deficiency (MSD). A paralogous gene, SUMF2, was discovered through its sequence similarity to SUMF1. We present evidence that SUMF2 colocalizes with SUMF1 within the endoplasmic reticulum and that the two proteins form heterodimers. SUMF1 and SUMF2 also form homodimers. In addition, SUMF2 is able to associate with the sulphatases with and without SUMF1. We have previously shown that co-transfection of SUMF1 with the sulphatase complementary DNAs greatly enhances the activities of the overexpressed sulphatases. Here, we show that SUMF2 inhibits the enhancing effects of SUMF1 on sulphatases, suggesting that the SUMF1–SUMF2 interaction represents a further level of control of these sulphatase activities.

Secondary Hemophagocytosis in Propionic Acidemia.

Secondary Hemophagocytosis in Propionic Acidemia.

96 The Leukoencephalopathies of Childhood: Findings From a National Prospective Study

Background and aims: To report the distribution of leukoencephalopathies in children identified by this prospective population-based study. Methods: 2802 children with suspected progressive intellectual and neurological deterioration (PIND) were notified via the British Paediatric Surveillance Unit (BPSU) between 1997 and 2009. An expert group reviewed clinical data and confirmed diagnoses where possible. An independent expert reviewed the available scans of children with unclassified leukoencephalopathies. Results: 1132 of the PIND children had an underlying diagnosis and of these 295 had one of the leukoencephalopathies. The distribution of diagnosed leukoencephalopathies was as follows: metachromatic leukodystrophy 62, X-linked adrenoleukodystrophy 60, Krabbe disease 39, Canavan disease 16, Alexander disease 13, leukoencephalopathy with vanishing white matter 12, Aicardi-Goutieres syndrome 12, Pelizaeus-Merzbacher disease 11, megalencephalic leukoencephalopathy with subcortical cysts 8, multiple sulphatase deficiency 6, multiple sclerosis 3, peroxisomal bifunctional D-protein deficiency 2, peroxisomal biogenesis defect 1. There were 50 children in the unclassified leukoencephalopathy group. In 32 the scans were reviewed and 19 were placed in a hypomyelination sub-group, the other 13 remaining in the unclassified leukoencephalopathy group with the 18 whose scans could not be reviewed. Conclusions: Leukoencephalopathies comprised 26% of PIND children with a known diagnosis. This population based study gives the relative frequency of the different leukoencephalopathies, providing an aid to diagnosis in children with abnormal white matter on brain imaging. After rigorous investigation 16% (50/295) remained in an unclassified group, but this situation is evolving.

Serial magnetic resonance imaging and neurophysiological studies in multiple sulphatase deficiency

We present serial clinical, magnetic resonance imaging (MRI) and neurophysiological findings of a patient with multiple sulphatase deficiency (MSD), who was first admitted at the age of 9 months, because of psychomotor retardation. MRI demonstrated extensive diffuse symmetrical high signal in the deep white matter of both cerebral hemispheres, as well as of the subcortical white matter and the brainstem, while there was additional enlargement of sulci and subdural spaces and mild atrophy. Assay of arylsulphatase A activity in white blood cell homogenates at the age of 29 months disclosed a marked deficiency of the enzyme, compatible with the diagnosis of early-infantile metachromatic leukodystrophy. During the course of a later admission, the presence of ichthyosis pointed out to the possible diagnosis of MSD; further assays of sulphatases in plasma, leukocytes as well as in cultured fibroblasts, combined with an abnormal excretion of mucopolysaccharides and sulphatides in urine confirmed the diagnosis. Molecular analysis identified a homozygous disease-causing mutation (R349W) of the SUMF1 gene. Serial neurophysiological and MRI studies demonstrated the progressive nature of the disorder (regarding both central and peripheral nervous system), correlating with the clinical deterioration (spastic quadriplegia, optic atrophy and epilepsy) with subsequent death at the age of 4 years.

Sulphatase activities are regulated by the interaction of sulphatase‐modifying factor 1 with SUMF2

Sulphatases undergo a unique post-translational modification that converts a highly conserved cysteine located within their active site into formylglycine. This modification is necessary for the catalytic activities of the sulphatases, and it is generated by the protein product of sulphatase-modifying factor 1 (SUMF1), the gene mutated in multiple sulphatase deficiency (MSD). A paralogous gene, SUMF2, was discovered through its sequence similarity to SUMF1. We present evidence that SUMF2 colocalizes with SUMF1 within the endoplasmic reticulum and that the two proteins form heterodimers. SUMF1 and SUMF2 also form homodimers. In addition, SUMF2 is able to associate with the sulphatases with and without SUMF1. We have previously shown that co-transfection of SUMF1 with the sulphatase complementary DNAs greatly enhances the activities of the overexpressed sulphatases. Here, we show that SUMF2 inhibits the enhancing effects of SUMF1 on sulphatases, suggesting that the SUMF1-SUMF2 interaction represents a further level of control of these sulphatase activities.

Cerebral Lipidoses in Patients with Progressive Neurodegeneration: A Study from South India

Objective: To study the prevalence and clinical profile of cerebral lipidoses in patients with progressive neurodegeneration. Subjects and Methods: A total of 771 patients clinically diagnosed with a progressive neurodegenerative disease were investigated for lipidoses. Specific enzyme assays in serum and leucocytes and other relevant investigations, including histopathology, neuroimaging and neurophysiological studies were conducted when indicated. Results: Fifty-four cases of sphingolipidoses and 1 case of sialidosis type 1 were diagnosed. The sphingolipidoses consisted of 30 cases of metachromatic leukodystrophy, 13 cases of Tay-Sachs disease and its variants, 11 cases of Sandhoff disease, and 1 case each of Niemann-Pick disease and multiple sulphatase deficiency. The clinical features were similar to earlier reports. Parental consanguinity was present in 63.6% of patients. Conclusions: In south India, where consanguineous marriages are strongly favoured, inherited diseases such as the cerebral lipidoses should be considered when evaluating a patient with progressive neurodegeneration. The establishment of specialised referral centres would provide a helpful approach to the prevention and management of these fatal disorders.

Immortalization and characterization of a cell line exhibiting a severe multiple sulphatase deficiency phenotype.

Multiple sulphatase deficiency (MSD) is a rare genetic defect that causes a simultaneous deficiency of all known sulphatases. All available evidence suggests that the deficient gene product is normally responsible for the post-translational modification of a conserved cysteine residue to 2-amino-3-oxopropionic acid and that this modification is necessary for sulphatase activity. MSD often has an enzymically mild phenotype, with significant levels of residual sulphatase activity being detectable. Here we identify an MSD cell line in which the residual activity of the sulphatases assayed was generally very low. To characterize the phenotype of this cell line further, immortalized lines were established after transformation with simian virus 40 (SV40) T antigen. Immortalized cell lines representing normal and MSD phenotypes were then transduced with a retroviral vector carrying the gene encoding human N-acetylgalactosamine-4-sulphatase. Analysis of N-acetylgalactosamine-4-sulphatase protein synthesis and enzyme activity showed that transduced cell lines expressed large amounts of enzyme and that the specific activity of this enzyme was approx. 0.5-1.5% of normal, confirming that this cell line defines a severe phenotype for MSD. N-Acetylgalactosamine-4-sulphatase purified from a transduced MSD cell line seemed normal on denaturing PAGE. Kinetic analysis of the purified enzyme suggests that the residual activity is due to small amounts of normal enzyme rather than unmodified enzyme with low levels of residual activity. These cell lines and the availability of large amounts of inactive N-acetylgalactosamine-4-sulphatase from MSD cells should facilitate the further study of this disorder.

Functional compartments of sulphatide metabolism in cultured living cells: evidence for the involvement of a novel sulphatide-degrading pathway

The modes of uptake and degradation of radiolabelled cerebroside sulphate (CS or sulphatide) were investigated in cultured living skin fibroblasts and Epstein-Barr virus-transformed lymphoblastoid cell lines established from control individuals and patients affected with metachromatic leucodystrophy (cerebroside sulphatase deficiency), multiple sulphatase deficiency and low-density-lipoprotein-receptor-negative familial hypercholesterolaemia. In both cell types, CS was taken up through a non-receptor-mediated process. In fibroblasts, CS degradation occurred intralysosomally as was evident from the findings that fibroblasts from metachromatic leucodystrophic patients accumulated the sulphatide and that chloroquine inhibited its degradation by normal cells. In contrast, under similar conditions of CS availability, lymphoblastoid cell lines from patients with metachromatic leucodystrophy could degrade the incorporated sulphatide exactly as their normal counterparts. This metabolic pathway was also fully active in lymphoblastoid cells from patients with multiple sulphatase deficiency and was not inhibited by chloroquine treatment. These data are consistent with a non-lysosomal type of hydrolysis. In addition to the lysosomal and non-lysosomal compartments, a third compartment was identified in the two cell types which is probably formed by the pool of the sulphatide molecules incorporated into the plasma membrane. This is the first report on the existence of a CS-degrading pathway in intact cells with deficient lysosomal cerebroside sulphatase activity.

Overexpression of N-acetylgalactosamine-4-sulphatase induces a multiple sulphatase deficiency in mucopolysaccharidosis-type-VI fibroblasts

High-titre stocks of an amphotropic retrovirus, constructed so as to express a full-length cDNA encoding the human lysosomal enzyme N-acetylgalactosamine-4-sulphatase (4-sulphatase) from the cytomegalovirus immediate early promoter, were used to infect skin fibroblasts from a clinically severe mucopolysaccharidosis type VI (MPS VI) patient. The infected MPS VI cells showed correction of the enzymic defect with the enzyme being expressed at high levels and in the correct subcellular compartment. Surprisingly this did not result in correction of glycosaminoglycan turnover as measured by accumulation of 35S in metabolically labelled cells. We demonstrate that this is apparently caused by an induced reduction of the activities of other lysosomal sulphatases, presumably due to competition for a sulphatase-specific processing mechanism by the over-expressed 4-sulphatase. The level of steroid sulphatase, which is a microsomal sulphatase, was also reduced. Infection of skin fibroblasts from a second, clinically mildly affected, MPS VI patient with the same virus also resulted in no significant change in the level of glycosaminoglycan storage. However, in this case the cause of the observed phenomenon was less clear. These results are of obvious practical importance when considering gene therapy for a sulphatase deficiency such as MPS VI and also provide possible new avenues for exploration of the processes involved in sulphatase synthesis and genetically determined multiple sulphatase deficiency.

N-acetylglucosamine 6-sulphatase deficiency in a Nubian goat: a model of Sanfilippo syndrome type D (mucopolysaccharidosis IIID).

A male Nubian goat (SD-1) presented at birth with neurological manifestations consistent with a lysosomal storage disease. Histological studies of tissue obtained at autopsy suggested glycosaminoglycan storage. Total urinary glycosaminoglycan levels, as measured by the uronic acid method, were elevated but overlapped with levels in a younger control goat. However, N-sulphate content was increased 2- to 5-fold, suggestive of heparan sulphate excretion, and this elevation was confirmed by cellulose acetate electrophoresis. Further, urinary levels of free N-acetylglucosamine 6-sulphate were increased 6-fold over controls, SD-1 cultured skin fibroblasts, labelled with [35S]sulphate from the incorporated twice as much radioactivity into macromolecular material as did normal fibroblasts. Forty-eight hours after removal of [35S]sulphate from the medium the SD-1 fibroblasts retained 58% of the label, whereas in control fibroblasts it had declined to 20%, indicative of [35S]proteoglycan storage in SD-1. The assay of fibroblast extracts revealed a profound deficiency of N-acetylglucosamine 6-sulphatase whereas eight other activities including beta-mannosidase, arylsulphatase B, iduronate 2-sulphatase, N-acetylgalactosamine 6-sulphatase, and heparin sulphamidase were normal. Mixing of SD-1 sonicates with normal sonicates showed no evidence of an inhibitor, and mixing of SD-1 sonicates with Sanfilippo D cell sonicates yielded no activity. These data ruled out multiple sulphatase deficiency and suggested the first example of the human Sanfilippo syndrome, type D (N-acetylglucosamine 6-sulphatase deficiency) in goats.

Human N-acetylgalactosamine-4-sulphatase biosynthesis and maturation in normal, Maroteaux-Lamy and multiple-sulphatase-deficient fibroblasts

The biosynthesis and maturation of N-acetylgalactosamine-4-sulphatase (4-sulphatase) was studied in normal fibroblasts and in fibroblasts from patients with either mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome) or multiple sulphatase deficiency (MSD). Fibroblasts were incubated in culture medium containing [3H]leucine or [35S]methionine, and radiolabelled 4-sulphatase was isolated by immunoaffinity chromatography using 4-sulphatase-specific monoclonal antibodies. In normal fibroblasts a precursor of 66 kDa, detected intracellularly after 3 h and in NH4Cl-induced secretions, was processed intracellularly, within an additional 3 h, to a polypeptide of 57 kDa composed of disulphide-linked polypeptides of 43 kDa and 8 kDa. All fibroblast lines obtained from MPS VI patients, exhibiting clinical characteristics ranging from no clearly recognized symptoms to the severe classical phenotype, incorporated radioactivity into immune-purified 4-sulphatase at a rate less than 10% of that seen in normal fibroblasts. Maturation of the residual 4-sulphatase showed, variously, features which may be indicative of delayed intracellular transport, decreased intracellular stability, failure of lysosomal targetting or resistance to enzyme processing. Although some features of the residual enzyme synthesis and maturation were consistent with the patient's clinical phenotype, this was infrequent. The maturation of 4-sulphatase in fibroblasts from MSD patients was indistinguishable from that in normal fibroblasts, and the half-life of 4-sulphatase in these fibroblasts, determined after a 24 h pulse and prolonged chase, was only slightly less than that in normal fibroblasts.

Prevalence of different types of lysosomal storage diseases in saudi arabia

The frequency of different types of lysosomal storage diseases in 125 referred cases, collected over three years, was compared to the occurrence elsewhere. The data suggest that mucopolysaccharidosis (MPS) type IVA (Morquio disease), multiple sulphatase deficiency, Niemann-Pick disease type B, GM2 gangliosidosis type '0' (Sandhoff disease), and ceroid lipofuscinosis (Jansky-Bielschowsky and Batten-Spielmeyer-Vogt syndromes) are encountered frequently in Saudi Arabia, as compared to other storage diseases. In contrast, some other diseases such as the adult variant of Gaucher's disease were not observed. Half of the GM2 gangliosidosis type '0' cases originated from one large tribe in the country. Other conditions did not show tribal predilection. The ceroid lipofuscinosis cases in Saudi Arabia originated from four large families. Consanguineous marriages taking place within tribal boundaries probably account for the pattern observed.

Multiple sulphatase deficiency: Prenatal diagnosis using chorionic villi

Multiple sulphatase deficiency was diagnosed in the first trimester of pregnancy by demonstrating markedly reduced activities of arylsulphatases and heparin sulphamidase by direct assays on chorionic villi (CV). The diagnosis was confirmed by assays on cell cultures of villi and fetal skin fibroblasts. Two further pregnancies of this mother were monitored similarly and predicted to be unaffected; one produced a normal healthy infant, the other miscarried shortly after CV sampling.

Multimodal evoked potential studies in leukodystrophies of children.

Evoked potentials were studied in 22 children with leukodystrophy [10 metachromatic leukodystrophy (MLD), 4 Pelizaeus-Merzbacher (PM), 3 Krabbes, 2 adrenoleukodystrophy (ALD), and one each of Alexander's, Canavan's and multiple sulphatase deficiency (MSD) diseases]. The ABRs were abnormal in all patients (except for the younger ALD), but varied with the type of leukodystrophy. The PM and Krabbes patients had abnormal ABRs with a loss of the rostral waves, accompanied in Krabbes with delayed I-III interpeak latencies; in MLD, ALD and MSD prolonged interpeak latencies were found. Three patients who had no clinical signs, but were positively diagnosed as MLD on the basis of absent arylsulphatase A, also had abnormal ABRs. The SEPs were abnormal in all patients. Cortical SEPs were absent in 16 and abnormal in 5 who were in the earlier stages of their disease. Cervical SEPs were within normal limits except for the Krabbes and MLD patients studied, who showed peripheral slowing. The VEPs were normal in only 6 and, unlike the ARBs and SEPs, did not seem to covary with clinical severity across the various leukodystrophies but did correlate with disease progression. Thus, multimodal EPs are useful in the diagnostic differentiation of the leukodystrophies.

Genetic complementation of steroid sulphatase after somatic cell hybridization of X-linked ichthyosis and multiple sulphatase deficiency.

Complementation studies of steroid sulphatase were carried out in the heterokaryon population of fibroblasts derived from patients with X-linked ichthyosis and multiple sulphatase deficiency. The activity of steroid sulphatase of the fused cell population was constantly higher (approximately 2-5 fold) than that of the unfused cocultivated cells. The occurrence of complementation further supports the hypothesis that at least two different loci control the expression of steroid sulphatase in the human genome.

Diagnosis of classical Morquio's disease: N-acetylgalactosamine 6-sulphate sulphatase activity in cultured fibroblasts, leukocytes, amniotic cells and chorionic villi.

The tritiated disulphated trisaccharide 6-sulpho-N-acetylgalactosamine-glucuronic acid-6-sulpho-N-acetyl-[1-3H]galactosaminitol was prepared from chondroitin 6-sulphate for use as a substrate for N-acetylgalactosamine 6-sulphate sulphatase. The reaction product was separated on ECTEOLA cellulose rather than Dowex 1 X 2. The mean activities of normal fibroblasts, leukocytes and amniotic cells were 8.43, 2.59 and 3.14 nmol h-1 mg protein-1, respectively. Fibroblasts from five patients with classical Morquio's disease (mucopolysaccharidosis IVA; MPSIVA) and one patient with neonatal multiple sulphatase deficiency displayed activities of less than 5% of control mean. Activity in amniotic cells from a pregnancy where the fetus was affected with MPS IVA was 6% of control mean. Activity was also found to be present in normal specimens of chorionic villi (mean value 1.21 nmol h-1 mg protein-1), demonstrating the feasibility of first trimester prenatal diagnosis of MPS IVA by assay of activity in this tissue.

Ito cells in lysosomal storage disorders. An ultrastructural study.

An ultrastructural study was performed in a series of liver biopsies from patients with various lysosomal storage diseases to evaluate the extent of lysosomal hypertrophy and hyperplasia in Ito cells (ICs). In previous studies this has been considered to be absent or only rudimentary. Lysosomal storage was recognized by the presence of storage cytosomes surrounded by limiting membranes and by the appearance of their content which was identical to that in other hepatic storage lysosomes. Storage was found in sphingomyelinase deficiency (Niemann-Pick disease types A, B), in Wolman's disease, GM1 gangliosidosis, mucopolysaccharidosis and in multiple sulphatase deficiency. In type C Niemann-Pick disease it was virtually absent with the exception of cases with prominent hepatic symptomatology. Storage was of variable degree and was accompanied by a decrease in the physiological fat content (cytoplasmic lipid droplets). The degree to which ICs were affected correlated only with the extent to which nonspecific fibroblasts were involved in the specimens studied and thus seems to reflect storage in the fibroblastic population.

Neonatal multiple sulphatase deficiency disorder: biochemical characterization.

AbstractRecently, Vamos et al. (1981) reported that the clinical features in the neonatal onset form of multiple sulphatase deficiency (MSD) were much more pro nounced than those of the usual type of MSD. The activities of arylsulphatases A, B and C in the patient's cultured skin fibroblasts were greatly reduced. This paper characterizes the biochemical features of neonatal MSD and distinguishes this disorder from typical MSD.