Moroccan Experience of Targeted Screening for Inborn Errors of Metabolism by Tandem Mass Spectrometry.

BACKGROUND: Expanded newborn screening using tandem mass spectrometry (MS/MS) for inborn errors of metabolism (IEM), such as organic acidemias (OAs), fatty acid oxidation disorders (FAODs), and amino acid disorders (AAs), is increasingly popular but has not yet been introduced in Africa. With this study, we aim to establish the disease spectrum and frequency of inborn errors of OAs, FAODs, and AAs in Morocco. METHODS: Selective screening was performed among infants and children suspected to be affected with IEM between 2016 and 2021. Amino acids and acylcarnitines spotted on filter paper were analyzed using MS/MS. RESULTS: Out of 1178 patients with a clinical suspicion, 137 (11.62%) were diagnosed with IEM, of which 121 (88.3%) patients suffered from amino acids disorders, 11 (8%) were affected by FAOD, and 5 (3.7%) by an OA. CONCLUSIONS: This study shows that various types of IEM are also present in Morocco. Furthermore, MS/MS is an indispensable tool for early diagnosis and management of this group of disorders.

[Diagnosis and monitoring of phenylketonuria by LC-MS-MS in Morocco]. / Diagnostic et suivi de la phénylcétonurie par LC-MS-MS au Maroc.

Phenylketonuria is an inherited metabolic disease, of autosomal recessive transmission, due to the enzymatic deficit of phenylalanine hydroxylase, which transforms phenylalanine into tyrosine. The deficit leads to an increase in phenylalanine and its metabolite, phenylpyruvic acid which is responsible for the toxicity and symptomatology characterized by serious neurological disorders. Through this work, we wanted to show: 1) the profile of phenylalanine concentrations in a cohort of 52 Moroccan phenylketonuric patients diagnosed in our laboratory by Tandem Mass Spectrometry coupled with HPLC; 2) The value of biological monitoring in the nutritional management of phenylketonuric patients. The results showed that phenylketonuria diagnosed in Morocco is characterized by a predominance of classic and moderate phenylketonuria in both sexes with a median concentration = 1,107 µmol/L, 26 times higher than that observed in the control group (median value = 42 µmol/L - p < 0.0001). The phenylalanine and tyrosine concentrations of 33 phenylketonuric patients regularly monitored by our laboratory highlights the effectiveness of the hypoproteic diet with a marked improvement in psychomotor development, a significant regression in behavioral disorders and an encouraging overall development of children. Conclusion: phenylketonuria is a disease that would be frequent in Morocco but it is still diagnosed at the stage of severe mental retardation. A better management of these patients could be considered when setting up a nation-wide neonatal screening program.