PHKA2 and glycogen storage disease IXb: In this study, we identified a previously reported homozygous pathogenic nonsense variant (c.2839 C > T) in the PHKB gene in one patient (P17) [42] who had elevated liver enzymes, similar to our patient in addition to a marked reduction in phosphorylase kinase (PhK) enzyme activity, which confirms the diagnosis of GSDIXb.