Diagnosis: Cobalamin C deficiency
Treatment: Hydroxocobalamin Acetate
The insurer denied Hydroxocobalamin Acetate.
The health plan's determination is overturned.

The patient is a female child with medical history significant for cobalamin C deficiency, autism, speech and language deficits, and developmental delay. She receives comprehensive supportive therapy services through her school. Her treatment regimen includes leucovorin, levocarnitine, betaine, folate, and hydroxycobalamin (currently at 10 mg [milligrams] dosing).

Hydroxycobalamin Acetate is medically necessary for this patient.

Cobalamin C deficiency is a type of remethylation defect inherited in an autosomal recessive pattern. This deficiency involves an impaired methylation of homocysteine to methionine resulting in accumulation of homocysteine. Patients with remethylation defects typically present with developmental and neurocognitive impairment, feeding difficulties with failure to thrive, neurological problems such as seizures and movement disorders, visual impairment, and hematological abnormalities. Patients specifically with cobalamin C deficiency may be prone to microangiopathic diseases such as atypical hemolytic uremic syndrome. Treatment involves early administration of hydroxycobalamin with a starting dose of 1000 mcg (micrograms; or 1 mg) intramuscularly daily for neonates titrated to effect, sometimes requiring significantly higher dosing and intervals of administration up to a week. Additional medications may include folate, betaine, and carnitine. The current standard involves treatment with hydroxycobalamin and betaine, with less evidence for the utility of carnitine treatment and dietary manipulations.

This young girl has been diagnosed with cobalamin C deficiency. Appropriate treatment involves hydroxycobalamin intramuscular injection. For her, the dose has been titrated up to 10 mg to achieve the desired clinical effects and prevent progression of the disease. Intramuscular injection in the most humane way entails using the more concentrated formulation (10 mg/mL [milligrams/milliliter] rather than 1mg/mL). This formulation is medically necessary and appropriate to achieve patient compliance and adequate management of a potentially devastating disease.