Multiple voxel 1H MR spectroscopy of phosphorylase-b kinase deficient patients (GSD IXa) showing an accumulation of fat in the liver that resolves with aging

Background/Aims Phosphorylase-b deficient patients suffer from glycogen storage disease (GSD IXa) leading to liver enlargement which usually resolves during puberty and adolescence. This pathology has not yet been documented by 1H MR spectroscopy (MRS) investigation. Methods MRS of eight GSD IXa patients was performed in this study to assess whether or not liver fat content is elevated in GSD IXa and decreases with aging. An improvement in our MRS method compared with previous liver fat MRS studies is that we measured a plane of liver voxels at once rather than a single MRS voxel, yielding a reliable determination of liver fat content. Results Fat contents of 3.4–10% were observed in young GSD IXa patients, as compared with 0.5–0.9% in controls, these dropped to control levels in patients past age 40 (r = −0.82; P < 0.01). Conclusions Liver fat content is increased in glycogen storage disease (GSD IXa) and normalizes with ageing. Assessing liver fat levels in this population is a novel and interesting concept. This could potentially enhance the understanding of liver function in that 20% of the population who has increased liver fat.