Sly syndrome, also called Mucopolysaccharidosis Type VII or MPS, is an autosomal recessive lysosomal storage disease

Lysosomal storage disease

Lysosomal storage diseases are a group of approximately 50 rare inherited metabolic disorders that result from defects in lysosomal function...

 characterized by a deficiency of the enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 β-glucuronidase, a lysosomal enzyme. Sly syndrome belongs to a group of disorders known as mucopolysaccharidoses, which are lysosomal storage diseases. In Sly syndrome, the deficiency in β-glucuronidase leads to the accumulation of certain complex carbohydrate

Carbohydrate

A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

s (mucopolysaccharides) in many tissues and organs of the body.

It was named after its discoverer William Sly in 1969 who has spent nearly his entire academic career at Saint Louis University.

Genetics

The defective gene responsible for Sly syndrome is located on chromosome 7.

Symptoms

The symptoms of Sly syndrome are similar to those of Hurler syndrome

Hurler syndrome

Hurler syndrome, also known as mucopolysaccharidosis type I , Hurler's disease, also gargoylism, is a genetic disorder that results in the buildup of glycosaminoglycans due to a deficiency of alpha-L iduronidase, an enzyme responsible for the degradation of mucopolysaccharides in lysosomes...

 (MPS I). The symptoms include:

• in the head, neck, and face: coarse (Hurler-like) facies and macrocephaly, frontal prominence, premature closure of sagittal lambdoid sutures, and J-shaped sella turcica
• in the eyes: corneal opacity and iris colobmata
• in the nose: anteverted nostrils and a depressed nostril bridge
• in the mouth and oral areas: prominent alveolar processes and cleft palate
• in the thorax: usually pectus carinatum
  Pectus carinatum
  Pectus carinatum, , also called pigeon chest, is a deformity of the chest characterized by a protrusion of the sternum and ribs. It is the opposite of pectus excavatum.-Causes:...
  
  or exacavatum and oar-shaped ribs; also a protruding abdomen and inguinal or umbilical hernia
• in the extremities: talipes, an underdeveloped ilium, aseptic necrosis of femoral head, and shortness of tubular bones occurs
• in the spine: kyphosis or scoliosis and hook-like deformities in thoracic and lumbar vertebrate
• in the bones: dysostosis multiplex

In addition recurrent pulmonary infections occur. Hepatomegaly occurs in the gastrointestinal system. Splenomegaly occurs in the hematopoietic system. Inborn mucopolysaccharide metabolic disorders due to β-glucuronidase deficiency with granular inclusions in granulocytes occurs in the biochemical and metabolic systems. Growth and motor skills are affected, and mental retardation also occurs.

Other names

Mucopolysaccharidosis Type VII is also known as β-glucuronidase deficiency, β-glucuronidase deficiency mucopolysaccharidosis,
GUSB deficiency, mucopolysaccharide storage disease VII, MCA, and MR.

External links

• The Matthew Evangelista Foundation Inc. is a charity that is trying to raise money to find treatment for Sly syndrome.
• http://www.mpssociety.org/