Mucopolysaccharidosis type 2?

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. This disease is a very important type of lysosomal storage disease?

Mucopolysaccharidosis type 2?

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. 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.

The head is large, boat shaped, with prominent forehead, dense eyebrows, prominent eyes, swollen eyelids, low and flat bridge of nose, and 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. Large joints, such as elbow joint, shoulder joint and knee joint, are involved to limit the range of motion of these joints; The joint of the hand is involved, showing the characteristics of "claw hand".

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.

matters needing attention

So far, there is no good way to treat this disease, but the curative effect is not ideal. Enzyme replacement and gene therapy are being studied. According to the special clinical manifestations of the disease, combined with family history, X-ray examination and laboratory examination, the diagnosis can be made. High risk families need prenatal diagnosis to prevent the same family from being born with the disease again.