Review Question - QID 109697

This patient is presenting with intellectual disability and a Marfanoid habitus suggesting a diagnosis of homocystinuria. Vitamin B6 (pyridoxine) can decrease the risk of cardiac complications.

Homocystinuria can present in young children with Marfanoid habitus, intellectual disability, osteoporosis, lens dislocation, and vascular complications (MI or stroke for example). Supplementation with vitamins B9, B12, and B6 can decrease homocysteine levels by serving as cofactors for the enzymes that break down homocysteine. Vitamin B6 serves as a cofactor for cystathionine synthase and breaks down homocysteine into cystathionine.

Rahman et al. review the evidence regarding the diagnosis and treatment of homocystinuria. They discuss how the early recognition of this disease can allow for lifestyle modifications and vitamin supplementation. They recommend the initiation of these changes in order to decrease cardiac morbidity and mortality.

Incorrect Answers:
Answer 1: Fish oil can decrease cardiovascular risk in some patients; however, it is less likely to decrease mortality from a cardiac cause as compared to pyridoxine in a patient with homocystinuria.

Answer 2: Iron could be used to treat microcytic anemia. Patients who suffer from long-term microcytic anemia are at risk for heart failure. This patient is suffering from a megaloblastic anemia which is being treated appropriately with vitamins B9 and B12.

Answer 3: No interventions would miss the critical supplementation of vitamin B6 in a patient with homocystinuria. These patients need vitamin supplementation in order to decrease the circulating levels of homocysteine and improve cardiac mortality.

Answer 5: Vitamin D is critical for calcium homeostasis and bone formation. It also plays a role in immunity. Deficiency of this vitamin is associated with states of fat intolerance such as cystic fibrosis or chronic pancreatitis.

Bullet Summary:
Patients with homocystinuria should be treated with vitamin B6, B9, and B12 supplements.