Mucopolysaccharidosis type VII as a cause of recurrent Non-Immune Hydrops Fetalis: The first Tunisian case confirmed by Next-Generation Sequencing

Non-Immune Hydrops Fetalis (NIHF) is an intrauterine condition characterized by excessive fluid accumulation in at least two fetal compartments in the absence of maternal circulating red cell antibodies. It is associated with a poor prognosis and a wide etiological spectrum. Among the metabolic causes, Mucopolysaccharidosis type VII depicts the most frequent type of lysosomal storage disorders in the cause of NIHF. Nonetheless, it remains an ultra-rare disorder, as less than 150 cases have been reported in the literature. This rarity seems to be related to misdiagnosis since the underlying etiology remains unelusive in most cases of NIHF. In this report, we describe the first Tunisian case of Mucopolysaccharidosis type VII caused by a homozygous mutation in the GUSB gene confirmed by a Next-Generation Sequencing gene panel in a patient with recurrent NIHF.