Infantile phosphofructokinase deficiency with arthrogryposis: clinical benefit of a ketogenic diet.

We report a 2-year-old boy with phosphofructokinase deficiency presenting in the newborn period with congenital arthrogryposis and severe myopathy, who has had significant improvement on a ketogenic diet since its institution at 4 months of age. We provide a rationale for use of this treatment and hypothesize it may be beneficial in other patients with phosphofructokinase deficiency and progressive muscular involvement. Confirmation awaits further clinical trials in carefully selected patients.