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Difference between revisions of "Homocystinuria"
(Created page with "<nowiki>= HOMOCYSTINURIA =</nowiki> These are a series of inborn errors of metabolism that are characterized by increased homocysteine levels in blood and urine. These are autosomal recessive disorders and are seen in 1 in 200,000 births. Normal homocysteine level in blood is 5–15 micromol/L. It can rise to 50-100 times the normal level in diseases. Moderate increase is seen in aged people, vitamin B12 or B6 deficiency, smokers and alcoholics and also in hypothy...") |
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=HOMOCYSTINURIA= | |||
These are a series of inborn errors of metabolism that are characterized by | These are a series of inborn errors of metabolism that are characterized by | ||
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function, and induction of thrombosis. | function, and induction of thrombosis. | ||
=Causes of homocystinuria= | |||
1. Cystathionine beta synthase deficiency (defective CBS gene) | 1. Cystathionine beta synthase deficiency (defective CBS gene) | ||
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3. Cobalamin (B12) deficiency. | 3. Cobalamin (B12) deficiency. | ||
=Clinical manifestations= | |||
1. Mental Retardation and Charlie Chaplin gait (Bilateral extorsion of the | 1. Mental Retardation and Charlie Chaplin gait (Bilateral extorsion of the | ||
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thrombosis due to activation of Hagemann’s factor (clotting factor XII). | thrombosis due to activation of Hagemann’s factor (clotting factor XII). | ||
=Diagnosis= | |||
Cyanide-Nitroprusside test is positive in urine. Urinary homocysteine exceeds | Cyanide-Nitroprusside test is positive in urine. Urinary homocysteine exceeds | ||
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300 mg/24 hours. | 300 mg/24 hours. | ||
Treatment | =Treatment= | ||
Diet low in methionine and vitamin B6 therapy along with folate and B12 | Diet low in methionine and vitamin B6 therapy along with folate and B12 | ||
supplements. Betaine therapy is usually added to the therapeutic regimen. | supplements. Betaine therapy is usually added to the therapeutic regimen. | ||
Revision as of 19:30, 19 February 2022
HOMOCYSTINURIA
These are a series of inborn errors of metabolism that are characterized by
increased homocysteine levels in blood and urine.
These are autosomal recessive disorders and are seen in 1 in 200,000 births.
Normal homocysteine level in blood is 5–15 micromol/L. It can rise to 50-100
times the normal level in diseases. Moderate increase is seen in aged people,
vitamin B12 or B6 deficiency, smokers and alcoholics and also in
hypothyroidism.
Elevated homocysteine levels in blood is associated with increased risk of
coronary artery disease through increased oxidant stress, impaired endothelial
function, and induction of thrombosis.
Causes of homocystinuria
1. Cystathionine beta synthase deficiency (defective CBS gene)
2. Deficient N 5 ,N 10 -Methyl THFA reductase (defective MTHFR gene)
3. Cobalamin (B12) deficiency.
Clinical manifestations
1. Mental Retardation and Charlie Chaplin gait (Bilateral extorsion of the
tibia).
2. Involvement in the eye: Ectopia Lentis (Subluxation of lens) and severe
Myopia are seen.
3. Increased platelet adhesiveness and increased risk of intravascular
thrombosis due to activation of Hagemann’s factor (clotting factor XII).
Diagnosis
Cyanide-Nitroprusside test is positive in urine. Urinary homocysteine exceeds
300 mg/24 hours.
Treatment
Diet low in methionine and vitamin B6 therapy along with folate and B12
supplements. Betaine therapy is usually added to the therapeutic regimen.