Clinical and Molecular Characterization of Mucopolysaccharidosis Type 3A and 3B in a Turkish Series

Abstract

Introduction: Sanfilippo syndrome or mucopolysaccharidosis type 3 (MPS-3) is a rare condition and its epidemiological data are still not defined. MPS-3 is linked to a deficiency in enzymes involved in heparan sulfate degradation. This biomolecule is neurotoxic and its accumulation underlies the severe central nervous system degeneration observed in this disease. Methods: Here, we describe 15 Turkish patients with MPS-3A or MPS-3B subtypes. Clinical data upon the diagnosis and during the follow-up as well as molecular characterization are reported. Results: Two and ten distinct variants were identified in SGSH and NAGLU gene sequences, respectively. Six variants (NAGLU NM_000263.3:c.532-?_c.764+?del, NAGLU NM_000263.3: c.509G>T, NAGLU NM_000263.3: c.700C>G, NAGLU NM_000263.3:c.507_516 del, NAGLU NM dises_000263.3: c.1354 G>A, NAGLU NM_000263.3: c.200T>C) have been previously published and 6 are novel (SGSH NM_000199.4: c.80T>G, SGSH NM_000199.4: c.7_16del, NAGLU NM_000263.3: c.224_235del, NAGLU NM_000263.3: c.904G>T, NAGLU NM_000263.3: c.626C>T, NAGLU NM_000263.3: c.1241A>G). SGSH NM_000199.4:c.7_16del variation might be caused by a founder effect. Conclusion: Due to the high rate of consanguinity in Turkey, the incidence of Sanfilippo syndrome might be higher compared to other populations worldwide. Our results contribute to the characterization of rare diseases in Turkey and to improve our knowledge of the clinical, molecular, and epidemiological aspects of MPS-3 disease.