Fig. 3From: Genetic testing is necessary for correct diagnosis and treatment in patients with isolated methylmalonic aciduria: a case reportTentative protocol for the recognition of Cbl sensitive forms of iMMA. Asymptomatic patients or patients stable without vitamin B12 treatment can undergo the test of responsiveness according to Fowler et al [14]. The sensitivity of unstable patients can be deduced from the results of genetic testing or enzymatic studies, if availableBack to article page