Sphingolipidoses in Morocco: Chemical profiling for an affordable and rapid diagnosis strategy

Sphingolipidoses are a group of metabolic diseases in which lysosomal hydrolases dysfunction disrupt normal sphingolipids' metabolism, leading to excess accumulation in cellular compartments and excretion in urine. These pathologies represent a significant burden among Moroccan population, for which an easy access to enzymatic assays and genetic tests is not guaranteed. Parallel analytical methods thus have to be developed for preliminary screening. In this study, 107 patients were addressed to the metabolic platform of the Marrakesh Faculty of Medicine for diagnosis confirmation. Thin-Layer Chromatography was used as a first step to perform chemical profiling of the patients' urinary lipids, allowing 36% of the patients to be efficiently oriented towards the adequate enzymatic assay. UPLC-MS/MS analyses of urinary sulfatides excreted in urines patient had been used to control the reliability of TLC analysis and to obtain more accurate information related to the sulfatides isoforms. This analytical process combining TLC with UPLC-MS/MS has enabled rapid and appropriate patient management in a reduced time and with reduced resources.

Clinical, biochemical and molecular characterization of Wilson's disease in Moroccan patients

Background

Wilson Disease (WD) is an autosomal recessive inherited metabolic disease caused by mutations in the ATP7B gene. WD is characterized by heterogeneous clinical presentations expressed by hepatic and neuropsychiatric phenotypes. The disease is difficult to diagnose, and misdiagnosed cases are commonly seen.

Methods

In this study, the presented symptoms of WD, the biochemical parameters as well as its natural history are described based on cases collected in Mohammed VI Hospital University of Marrakech (Morocco). We screened and sequenced 21 exons of ATP7B gene from 12 WD patients that confirmed through biochemical diagnosis.

Results

Mutational assessment of the ATP7B gene showed six homozygous mutations in 12 individuals however, 2 patients had no evidence of any mutation in promoter and exonic regions. All mutations are pathogenic and most were missense mutations. c.2507G > A (p.G836E), c.3694A > C (p.T1232P) and c.3310 T > C (p.C1104R) that were identified in 4 patients. The other mutations were a non-sense mutation (c.865C > T (p.C1104R)) detected in 2 patients, a splice mutation (c.51 + 4A > T) detected in 2 patients and a frameshift mutation (c.1746 dup (p.E583Rfs*25) detected in 2 patients.

Conclusion

Our study is the first molecular analysis in Moroccan patients with Wilson's disease, the ATP7B mutational spectrum in the Moroccan population is diverse and still unexplored.