Classification & external resources
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Morquio syndrome (referred to as mucopolysaccharidosis IV or Morquio) is a mucopolysaccharide storage disease (see also lysosomal storage disorder), usually inherited. It is a relatively rare dwarfism with serious consequences. Comes from parents that produce one gene of it, even normal healthy parents. When the body cannot process certain types of mucopolysaccharides, they build up or are eliminated, causing various symptoms.
Two forms are recognized, type A and type B.
- Type A is a deficiency of the enzyme N-acetylgalactosamine-6-sulfate sulfatase.
- Type B is a deficiency of the enzyme beta-galactosidase.
The condition was first described, simultaneously and independently, in 1929, by Luis Morquio in Montevideo, Uruguay, and by James Frederick Brailsford in Birmingham, England. They both recognized the occurrence of corneal clouding, aortic valve disease, and urinary excretion of keratan sulfate. Morquio observed the disorder in 4 siblings in a family of Swedish extraction and reported his observations in French.
The following symptoms are associated with Morquio syndrome:
- Abnormal heart development
- Abnormal skeletal development
- Hypermobile joints
- Large fingers
- Widely spaced teeth
- Coarse facial features
- Large head
- Bell shaped chest (ribs flared)
- Compression of spinal cord
- Death (When heart is too big for body)
- Dwarfism ( when a person is very small)
As most mucopolysaccharidoses, Morquio syndrome exhibits alterations in white blood cells that are diagnostic, and might allow for screening procedures and cost-effective differential diagnosis in the future. These anomalies can be best studied with Wright stain, the routine dye employed in hematology laboratory. Neutrophils in Morquio's syndrome exhibit persistence of the azurophilia in its granules, which is explained by the deficient enzyme's inability to clear them from mucopolysaccharides used as a tags in the cells vesicular sorting system. Approximately 70 percent of the neutrophils exhibit this subtle alteration. Differential diagnosis must be made with mucopolisaccharidoses I,II,III,VI and VII.
Nonetheless, after this screening procedure has been carried on, quantitative enzyme determination assays must be conducted to verify the diagnosis, should any replacement treatment is available.
Complications that may develop include:
- Heart failure
- Difficulty with vision
- Walking problems related to abnormal curvature of the spine
- Abnormal neck bones can cause spinal cord damage that can cause severe disease including paralysis if not caught early -- spinal fusion can prevent this
- Problems with urination
|Metabolic pathology / Inborn error of metabolism (E70-90, 270-279)|
|Amino acid||Aromatic (Phenylketonuria, Alkaptonuria, Ochronosis, Tyrosinemia, Albinism, Histidinemia) - Organic acidemias (Maple syrup urine disease, Propionic acidemia, Methylmalonic acidemia, Isovaleric acidemia, 3-Methylcrotonyl-CoA carboxylase deficiency) - Transport (Cystinuria, Cystinosis, Hartnup disease, Fanconi syndrome, Oculocerebrorenal syndrome) - Sulfur (Homocystinuria, Cystathioninuria) - Urea cycle disorder (N-Acetylglutamate synthase deficiency, Carbamoyl phosphate synthetase I deficiency, Ornithine transcarbamylase deficiency, Citrullinemia, Argininosuccinic aciduria, Hyperammonemia) - Glutaric acidemia type 1 - Hyperprolinemia - Sarcosinemia|
|Carbohydrate||Lactose intolerance - Glycogen storage disease (type I, type II, type III, type IV, type V, type VI, type VII) - fructose metabolism (Fructose intolerance, Fructose bisphosphatase deficiency, Essential fructosuria) - galactose metabolism (Galactosemia, Galactose-1-phosphate uridylyltransferase galactosemia, Galactokinase deficiency) - other intestinal carbohydrate absorption (Glucose-galactose malabsorption, Sucrose intolerance) - pyruvate metabolism and gluconeogenesis (PCD, PDHA) -
Pentosuria - Renal glycosuria|
|Lipid storage||Sphingolipidoses/Gangliosidoses: GM2 gangliosidoses (Sandhoff disease, Tay-Sachs disease) - GM1 gangliosidoses - Mucolipidosis type IV - Gaucher's disease - Niemann-Pick disease - Farber disease - Fabry's disease - Metachromatic leukodystrophy - Krabbe disease|
Neuronal ceroid lipofuscinosis (Batten disease) - Cerebrotendineous xanthomatosis - Cholesteryl ester storage disease (Wolman disease)
|Fatty acid metabolism||Lipoprotein/lipidemias: Hyperlipidemia - Hypercholesterolemia - Familial hypercholesterolemia - Xanthoma - Combined hyperlipidemia - Lecithin cholesterol acyltransferase deficiency - Tangier disease - Abetalipoproteinemia |
Fatty acid: Adrenoleukodystrophy - Acyl-coA dehydrogenase (Short-chain, Medium-chain, Long-chain 3-hydroxy, Very long-chain) - Carnitine (Primary, I, II)
|Mineral||Cu Wilson's disease/Menkes disease - Fe Haemochromatosis - Zn Acrodermatitis enteropathica - PO43�' Hypophosphatemia/Hypophosphatasia - Mg2+ Hypermagnesemia/Hypomagnesemia - Ca2+ Hypercalcaemia/Hypocalcaemia/Disorders of calcium metabolism|
and acid-base balance
|Electrolyte disturbance - Na+ Hypernatremia/Hyponatremia - Acidosis (Metabolic, Respiratory, Lactic) - Alkalosis (Metabolic, Respiratory) - Mixed disorder of acid-base balance - H2O Dehydration/Hypervolemia - K+ Hypokalemia/Hyperkalemia - Cl�' Hyperchloremia/Hypochloremia|
|Purine and pyrimidine||Hyperuricemia - Lesch-Nyhan syndrome - Xanthinuria|
|Porphyrin||Acute intermittent, Gunther's, Cutanea tarda, Erythropoietic, Hepatoerythropoietic, Hereditary copro-, Variegate|
|Bilirubin||Unconjugated (Lucey-Driscoll syndrome, Gilbert's syndrome, Crigler-Najjar syndrome) - Conjugated (Dubin-Johnson syndrome, Rotor syndrome)|
|Glycosaminoglycan||Mucopolysaccharidosis - 1:Hurler/Hunter - 3:Sanfilippo - 4:Morquio - 6:Maroteaux-Lamy - 7:Sly|
|Glycoprotein||Mucolipidosis - I-cell disease - Pseudo-Hurler polydystrophy - Aspartylglucosaminuria - Fucosidosis - Alpha-mannosidosis - Sialidosis|
|Other||Alpha 1-antitrypsin deficiency - Cystic fibrosis - Amyloidosis (Familial Mediterranean fever) - Acatalasia|