The Frequencies of Different Inborn Errors of Metabolism in Adult Metabolic Centres: 10 Years Later, Another Report From the SSIEM Adult Metabolic Physicians Group.

There are still few centres, which specialise in the care of adults with inborn errors of metabolism (IEM). All physicians who participated in the SSIEM adult metabolic physicians group paper in 2014 were contacted to provide updated data on their IEM patients. Fifteen adult centres responded to our survey with information on their patients. Nine thousand, six hundred fifty-one patients were included in the final cohort, compared with 6 182 in the previous analysis. There were 394 separate diagnoses. The most common diseases were phenylketonuria (19.6%), mitochondrial disorders (12.3%) and lysosomal storage disorders such as Fabry disease (20.1% of LSD's), Pompe disease (3.1%), and Gaucher disease (2.8%). Among the disorders that can present with acute metabolic decompensation, the urea cycle disorders (4.0%), were most common (ornithine transcarbamylase deficiency 2.6%), followed by maple syrup urine disease (1.1%) and glycogen storage disease type I (0.7%). Patients were frequently diagnosed as adults, particularly those with mitochondrial disease and lysosomal storage disorders. Many patients are only diagnosed in adulthood (> 40%) and the cohort is increasing substantially with 9 651 patients included in the final analysis (34% increase compared to our original paper). Thus reinforcing the need for adult specialists to be trained in this area.