Lysosomal Storage Disorders

Table of Lysosomal Storage Disorders

Storage Disorder Enzyme Deficiency Clinical Features

I. SPHINGOLIPIDOSES

Niemann-Pick disease, Type A Sphingomyelinase Neuropathic, foamy histiocytes in bone marrow, acute neuropathic progressive loss of motor and intellectual capacity early in life, hepatosplenomegaly, cherry-red macula, commonly fatal in infancy Niemann-Pick disease, Type B Sphingomyelinase Similar to Niemann-Pick disease, Type A but non-neuropathic and age of onset is slightly older Niemann-Pick disease, Type C Depressed cholesterol esterification and Psychomotor symptoms occurring in first year or abnormal filipin staining; 2 of life. Vertical supranuclear ophthalmoplegia; Sphingomyelinase may be depressed but hypertonic limbs and loss of coordination; not absent. organomegaly common, neonatal hepatitis and/or jaundice; mixed expression due to greater or lesser secondary liver involvement such that milder forms may be considered as described below as subacute. Gaucher disease ß-Glucosidase Type 1—Chronic non-neuropathic: hepatosplenomegaly, Gaucher cells, anemia, bone pain and lytic lesions, striking elevation of angiotensin converting enzyme. Most frequently occurring storage disease with the highest incidence in Ashkenazi Jews. ß-Glucosidase Type 2—Infantile acute neuropathic, rapidly degenerative central nervous system manifestations, peripheral symptoms similar to type 1 but greatly exaggerated, death usually occurs by 1 year of age. ß-Glucosidase Type 3—Subacute neuronopathic; similar to type 2 except later onset and a milder course eventually causing death in early childhood. Krabbe disease Galactosylceramide ß-galactosidase A number of forms are recognized, differing largely in age of onset and severity of symptoms, progressive psychomotor retardation, globoid cells in central nervous system, spastic quadriparesis, hypertonicity, hyperthermia, elevated cerebrospinal fluid protein. Metachromatic Arylsulfatase A Several closely related disorders with differing leukodystrophy (MLD) ages at onset from 1 year of age well into adulthood, peripheral neuropathy, intermittent pain in arms and legs with eventual difficulty sitting, gait disturbance, absence of deep tendon reflexes, plantar flexion of feet. Adult form— slowly progressive dementia; often confused with nonorganic psychoses. Storage Disorder Enzyme Deficiency Clinical Features Fabry disease α-Galactosidase Severe pain in extremities; on buttocks and around navel; tortuous, dilated conjunctival and retinal venules; neuropathy; hypertension; myocardial ischemia. Female carriers may show manifestations. Tay-Sachs disease Hexoaminidase A Early motor weakness, psychomotor deterioration after 1 year of age, progressive deafness, blindness, startle response, red macula. Sandhoff disease Hexosaminidase A and B Similar to Tay-Sachs but with mild peripheral neuropathy and organomegaly. GM1 gangliosidosis ß-Galactosidase Type 1—Severe mental retardation, and muscle hypotonicity apparent in first few months of life, dysostosis multiplex, foam cells in marrow. ß-Galactosidase Type 2—Regression of normal motor development apparent after age 1, seizures and rapidly progressive spasticity after first symptoms apparent, mild dysostosis multiplex. II. MUCOPOLYSACCHARIDOSES (MPS)

Hurler syndrome α-L-Iduronidase Progressive mental and physical debilitation (MPS IH) beginning at age 1, corneal opacities, coarse facies, gingival hyperplasia, dysostosis multiplex, stiff joints (claw-hands), dwarfing, organomegaly. Scheie syndrome α-L-Iduronidase A mild form of MPS IH with corneal opacity, (MPS IS) mild or absent mental retardation, claw-hand deformity, aortic stenosis. Hunter syndrome Iduronate sulfatases Dysostosis multiplex essentially the same as in (MPS II) MPS IH, mental retardation in the severe forms (syndrome runs gamut from severe to mild). Lack of corneal clouding; there is a longer life span of even the severest form. Sanfilippo syndrome Heparan N-sulfatase Behavioral problems progressing to severe mental (MPS IIIa) retardation, comparatively mild or nonexistent connective tissue abnormalities, pronounced hirsutism. Type a is the most common of the Sanfilippo’s syndromes. Sanfilippo syndrome α-N-Acetylglucosaminidase Indistinguishable clinically from MPS IIIa. (MPS IIIb) Sanfilippo syndrome α-Glucosaminide-N-acetyltransferase Indistinguishable clinically from MPS IIIa. (MPS IIIc) Sanfilippo syndrome N-Acetylglucosamine-6-sulfate sulfatase Indistinguishable clinically from MPS IIIa. (MPS IIId) Morquio disease Galactosamine-6-sulfate sulfatase Pronounced skeletal anomalies with small stature (MPS IVa) (short-trunk dwarfism), short neck, prominent lower ribs, odontoid anomalies, normal intellect. Morquio disease ß-Galactosidase Mild form of IVa, spondyloepiphyseal dysplasia, (MPS IVb) short stature, cloudy corneas, normal intellect. Maroteaux-Lamy disease Arylsulfatase B Severe-mild dysostosis multiplex, gross corneal (MPS VI) opacity, retardation of growth, normal intellect, cardiomyopathy. Sly disease ß-Glucuronidase Mild mental retardation, somewhat coarse facies, (MPS VII) gingivitis, organomegaly, sometimes with corneal clouding. Storage Disorder Enzyme Deficiency Clinical Features III. DISORDERS OF UNDEFINED AND/OR LIPID STORAGE PRODUCTS

Fucosidosis α-Fucosidase Type 1—Frequent respiratory infections, progressive psychomotor retardation, dysostosis multiplex (“Hurler-like”), thick skin with hypersecretion of sweat with elevated salinity, cardiomegaly. α-Fucosidase Type 2—Distinguished from type 1 by its milder clinical presentation and absence of unusual sweating; lesions (angiokeratoma) can be present. α-Mannosidase Mild hepatosplenomegaly, mild radiologic bone changes, psychomotor retardation, nerve deafness. IV. DISORDERS PRESUMED TO INVOLVE MULTIPLE STORAGE PRODUCTS

Mucolipidosis I (ML I) Neuraminidase and after ß-galactosidase Type I—(Normomorphic) Cherry-red spots of the () deficiency macula, myoclonus, normal intelligence. Neuraminidase Type II—(Dysmorphic) Dysostosis multiplex, mental retardation, myoclonus, cherry-red spots of the macula, both infantile and juvenile onset. II (ML II) UDP-N-acetylglucosemia: Early onset of Hurler-like symptoms (often noted (I-cell disease) glycoprotein N-acetylglucosaminyl- at birth), gingival hyperplasia, thoracic phosphotransferase deformities, hepatosplenomegaly. Mucolipidosis III (ML III) UDP-N-acetylglucosemia: Mild variant of ML II; slowly progressing Hurler- (pseudo-Hurler polydystrophy) glycoprotein N-acetylglucosaminyl- like features, particularly claw-hand deformity; phosphotransferase mild growth and mental retardation; joint stiffness with reduced mobility. Multiple sulfatase deficiency Deficiency of all lysosomal sulfatases to Similar to infantile metachromatic (MSD) greater or less degrees (arylsulfatase A less leukodystrophy but with the skeletal anomalies of than arylsulfatase B). mucopolysaccharidoses, hepatosplenomegaly, thickening of the skin, ichthyosis. α-N-Acetylgalactosaminidase (α- Onset at about 1 year followed by development galactosidase B) delay, and thereafter, psychomotor retardation, cortical blindness, spasticity, decorticate posturing. V. GLYCOGEN STORAGE DISORDERS

Pompe disease α-Glucosidase Though glycogen storage is ubiquitous to nearly (Type II GSD) (acid maltase) all tissues, cardiomegaly and hypotonia are the most life-threatening of the sequelae. There are multiple forms of the disease which give rise to infantile through adult presentation.