First 3 cases of glycogen storage disease type 1b diagnosed in Morocco: genetic and clinical features

Purpose: Glycogen storage disease type 1b (GSD1b) is a rare autosomal recessive metabolic defect of glycogenolysis and gluconeogenesis which results from a deficiency of the glucose-6-phosphate translocase. GSD 1b is characterized by chubby face, hypoglycemia, hyperlipidemia, hyperuricemia, hepatomegaly, nephromegaly and growth retardation. GSD1b patients also show neutropenia and/or neutrophil dysfunction that cause increased susceptibility to recurrent bacterial infections and inflammatory intestinal diseases. From 2010 to 2014, 3 cases of GSD1b were diagnosed in Morocco. The purpose of this paper is to report the clinical and genetic characteristics of those GSD1b patients.Methods: We investigated the genetic, immunological and clinical features of 3 Moroccan patients with GSD1b from 3 unrelated kindreds.Results: All patients experience chubby face, hepatomegaly, hypoglycemia, hypercholesterolemia / hypertriglyceridemia / hyperuricemia and failure to thrive. All cases suffered from recurrent bacterial and/or fungal infections due to neutropenia. The sequencing of SLC37A4 gene showed the same mutation c.1042_1043delCT in the homozygous state. In the absence of treatment with recombinant human granulocyte colony-stimulating factor (G-CSF), the evolution was marked by the death of two cases in an infectious context despite symptomatic and preventive treatment.Conclusion: Further studies on a large cohort are required to determine the incidence and prevalence of the disease, and to improve the description of the genetic and clinical features of GSD1b patients in Morocco.