OVERVIEW
Mannoside storage disease is a systemic disease caused by alpha-mannosidase deficiency. Clinical manifestations include progressive facial ugliness, giant tongue, flat nose, large ears, wide teeth, large head, large hands and feet, and hypotonia and bradykinesia of the extremities. There is no mucopolysacchariduria, but there is an increase in the mannose-containing components of the tissues.
Etiology
Caused by alpha-mannosidase deficiency.
Symptoms
According to the age of onset of the disease, those with severe mannoside storage disease and onset in infancy are called type I or infantile type; those with mild disease and onset in adolescence are called type II or juvenile type. In the former, the development is normal at birth, but around 1 year of age, there may be progressive facial ugliness, huge tongue, flat nose, large ears, wide teeth, large head, large hands and feet, low muscle tone of the limbs and motor retardation. The sternum is bulging, the chest and waist are hunched, the skull is thickened, the cornea is usually clear, but some children have cloudy crystals, and some of them are deaf or have speech disorders and mental retardation when they are first born. Type II most often develops after 2 years of age, with normal physical and psychomotor development, progressive cerebral developmental delay starting after 2 years of age, frequent respiratory infections, ugly face, thick eyebrows, widened spacing of incisors, convex jaw, low anterior hairline, and mild bilateral deafness (mostly sensory).
Examination
1. Some patients may have total blood loss.
2. X-ray examination.
3. biopsy of the liver and other tissues shows deficiency of acid-type alpha-mannosidase.
4. No excessive mucopolysaccharides are excreted in the urine.
Diagnosis
The disease is diagnosed on the basis of clinical symptoms, X-ray findings, liver and other tissue biopsies, and other relevant findings.
Treatment
There is no specific treatment, if necessary, surgery can be done to correct the bone deformity and antibiotics can be used to control the infection.
Prevention
Premarital examination, genetic counseling, prenatal examination and early treatment of genetic diseases.