GFER and glycogen storage disease Ib: In a patient diagnosed with a glycogen storage disease, GSD type Ib, caused by compound heterozygous variants in SLC37A4 (MIM 602671) and Dilated Cardiomyopathy (DCM) that is probably caused by a truncating variant in TTN (MIM 188840) HPO terms related to GSD type Ib (‘leukopenia’ (HP:0001882) and ‘inflammation of the large intestine’ (HP:0002037)) cluster together, while Cardiomyopathy (HP:0001638) was only weakly correlated to these specific features (Fig. 4b).