Question

Which amino acid needs to be supplemented through diet in patient with cystathionine beta synthase

• A. Cysteine
• B. Methionine
• C. Serine
• D. Tryptophan

Answer 1

The Correct Option is A

Cystathionine beta synthase (CBS) deficiency leads to an accumulation of homocysteine and methionine due to a disrupted transsulfuration pathway. CBS normally converts homocysteine and serine to cystathionine, eventually leading to the production of cysteine. When CBS is deficient, this conversion is impaired, necessitating cysteine supplementation through diet.

Explanation:

1. CBS Function: Converts homocysteine and serine to cystathionine.
2. Pathway Disruption: CBS deficiency leads to impaired cystathionine formation, reducing cysteine synthesis.
3. Dietary Requirement: Cysteine becomes essential and must be supplemented as the body cannot synthesize adequate levels without CBS activity.

Conclusion: Patients with CBS deficiency should supplement cysteine through their diet to compensate for the reduction in endogenous production due to the disrupted metabolic pathway.