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Introduction: Phosphoglucomutase 1 deficiency (PGM1 deficiency) has been identified as both, glycogenosis and congenital disorder of glycosylation (CDG). The phenotype includes hepatopathy, myopathy, oropharyngeal malformations, heart disease and growth retardation. Oral galactose supplementation at a dosage of 1 g per kg body weight per day is regarded as the therapy of choice. Results: We report on a patient with a novel disease causing mutation, who was treated for 1.5 years with oral galactose supplementation. Initially, elevated transaminases were reduced and protein glycosylation of serum transferrin improved rapidly. Long-term surveillance however indicated limitations of galactose supplementation at the standard dose: 1 g per kg body weight per day did not achieve permanent correction of protein glycosylation. Even increased doses of up to 2.5 g per kg body weight did not result in complete normalization. Furthermore, we described for the first time heart rhythm abnormalities, i.e. long QT Syndrome associated with a glycosylation disorder. Mass spectrometry of IGFBP3, which was assumed to play a major role in growth retardation associated with PGM1 deficiency, revealed no glycosylation abnormalities. Growth rate did not improve under galactose supplementation. Conclusions: The results of our study indicate that the current standard dose of galactose might be too low to achieve normal glycosylation in all patients. In addition, growth retardation in PGM1 deficiency is complex and multifactorial. Furthermore, heart rhythm abnormalities must be considered when treating patients with PGM1 deficiency.

Niemann Pick type C (NP-C) is a rare neurodegenerative disorder caused by an impairment of intracellular lipid transport. Due to the heterogeneous clinical phenotype and the lack of a reliable blood test, diagnosis and therapy are often delayed for years. In the cell, accumulating cholesterol leads to increased formation of oxysterols that can be used as a powerful screening parameter for NP-C. In a large scale study, we evaluated the oxysterol cholestane-3β,5α,6β-triol (c-triol) as potential biomarker for a rapid diagnosis of NP-C. Using GC/MS, c-triol has been analyzed in 1902 plasma samples of patients with the suspicion for NP-C. Diagnosis in patients with elevated oxysterols was confirmed by genetic analysis. 71 new NP-C patients (69 NP-C1 and two NP-C2) and 12 Niemann Pick type A/B patients were identified. 24 new mutations in NPC1, one new mutation in NPC2 and three new mutations in the SMPD1 gene were found. Cholestane-3β,5α,6β-triol was elevated in Niemann Pick type C1, type C2, type A/B and in CESD disease. No other study has ever identified so many NP-C patients, proving that c-triol is a rapid and reliable biomarker to detect patients with NP-C disease and related cholesterol transport disorders. It should replace the filipin test as the first-line diagnostic assay.