Homocystinuria

First, the preamble:
1, disease name:
Homocystinuria (Homocystinuria).
2, Origin:
Homocystinuria metabolism disorders are a group of rare congenital disorders, but each and every parent
The mother should have heard the name of the disease, because it is one of the items to neonatal screening.
Second, epidemiological studies:
Incidence: the Western countries an average of about one ten thousandth 20-30, Ireland up to 1/50000, Taiwan
Thirteen years in 19 cases, about 1/500000.
Three, pathogenesis:
Homocystinuria (Homocystinuria) as an autosomal recessive genetic disorders of metabolism.
Is divided into three types according to etiology:
Type: cystathionine synthase (Cystathionine-β-synthase) deficiency, caused by in vivo high-cystathionine
Arginine and methionine accumulation, interference with collagen cross-links, resulting in vascular endothelial, bone and other systems
Harm. In addition cystathionine synthase role of a cofactor required the help of vitamin B6.
II: methylcobalamin formation of defects (large ball anemia).
III: N (5,10)-methylentetrahydrofolate reductase-deficient (methionine Low).
2
Four clinical symptoms:
1, IQ:
Early untreated sick about 58 percent have mental retardation; in recent years, early diagnosis and treatment, about 16% (4 / 25),
The average IQ of 82-110.
2, eyes:
Myopia, lens dislocation (Ectopic lentis), more than 10 years ago, or have to report early
2-year-old emerged. Eyes will be accompanied by other symptoms, including myopia, glaucoma, cataract or
Retinal detachment.
3, skeletal:
skin,tall, spiders mean, chicken breast or pectus excavatum. Genu varum, air concave foot, osteoporosis, spinal
Compression fracture, spinal scoliosis after.
4, vascular:
Middle aortic degradation, elastic artery lining hyperplasia and fibrosis. Arteries and veins often suppository
Cypriot. Vascular embolization may cause ischemic brain or heart, or even cause the death of the surrounding
Blood vessels will also have the same changes, in fact, mental retardation may also be caused by vascular disease.
5, skin:
Malar flushing, erythema have other parts of the vulnerable.
6, hair:
Smaller, do,colorless, and sparse.
7, cramps:
Spasm in the six months to five seizures, EEG abnormalities. Excessive tension and occasional acts of schizophrenia.
Spastic muscles may occur.
Friday, diagnosis:
1, urine amino acids (urine to be fresh, because of instability Homocystine).
2, blood / skin / liver enzyme analysis.
3, gene analysis: poor correlation with the phenotype.
3
6, treatment:
1, vitamin B6 reaction type:
Have residual enzyme activity, with high doses of B6 100-1200mg / d can be. At the same time, supplementary folic acid (folic
acid).
2, vitamin B6 is not reactive:
Strictly limit the intake of methionine, added Cystine (special formula). Another added Betaine
(80-280mg / d), folic acid (1-5mg / d).
Seven, prevention and screening:
Newborn Screening: Birth day at heel mining as long as a few drops of blood, measuring blood volume of methionine on
Be able to tell whether a child suffers from certain congenital diseases.