Hypothesis: lobe A (COG1–4)-CDG causes a more severe phenotype than lobe B (COG5–8)-CDG

Some cellular components may be more equal than others.  In this study we used the frequency gap – underreporting of a certain phenomenon – to determine the relative importance of both A and B lobes for the functioning of a protein complex called “the COG complex”.  Two observations suggest that the consequences of lobe A dysfunction is more severe. First, patients with bi-allelic lobe A defects are underreported compared to lobe B defects. Second, deleterious variants in healthy adults are underreported in lobe A genes compared to lobe B genes. Much like driving a car is more hampered by a defective motor than by a defective gear case, comparable molecular defects are more detrimental in lobe A COG-CDG than in lobe B COG-CDG. (By Hanneke A. Haijes-Siepel and Dr. Peter M. van Hasselt, http://jmg.bmj.com/content/early/2017/08/27/jmedgenet-2017-104586 )