Mucopolysaccharidosis type I?

summary

Mucopolysaccharide storage disease is caused by the mutation of mucopolysaccharide degrading hydrolase in human cells, resulting in the loss of its activity. Mucopolysaccharide can not be degraded and metabolized, and finally stored in the body. The disease is a very important type of lysosomal storage disease, which can be divided into seven types, including type I, II, III, IV, VI, VII, IX. among them, type III can be divided into four subtypes, i.e. III A, III B, III C, III D. type IV can be divided into IV A and IV B subtypes. Although the pathogenic genes and clinical manifestations of each type are different, it is called mucopolysaccharidosis because the substrate of the accumulation is mucopolysaccharide.

Mucopolysaccharidosis type I?

Except for type II, mucopolysaccharidosis is an autosomal recessive genetic disease, which is caused by congenital defects of cytolysosomal acid hydrolase. It is characterized by excessive accumulation and excretion of oligosaccharides.

Rough face, large head, boat shaped head, prominent forehead, dense eyebrows, prominent eyes, swollen eyelids, low bridge of nose, upturned nostrils. The lips are large and thick; The tongue is large and easy to protrude. Gingival hyperplasia, small teeth and wide spacing. The skin is thick, the hair is thick and rough, and the hairline is low.

The symptoms of classic type II were milder than that of type I. this type was mainly male, and the cornea was not turbid; Mental retardation is the main clinical manifestation of type III patients; In type IV, the wrist joint is loose and the chest is protruding forward, similar to chicken breast; The intelligence of type VI patients was normal, and the corneal opacity was obvious; The difference of clinical manifestations of type VII patients can be very large, the serious manifestation is fetal edema, and the light patients can only have short stature.

matters needing attention

For example, dermatan sulfate and heparin sulfate bands were found in type I and type II patients, heparin sulfate bands were found in type III patients, and keratin sulfate bands were found in type IV patients. The urine mucopolysaccharide electrophoresis of type III and type IV patients is prone to false negative phenomenon.