Muccopolysaccharidosis Type II, Two Novel Mutations

MPS is an inherited metabolic disorder caused by absence or severe deficiency of one of the lysosomal enzymes that there main function is degradation of glycosaminoglycans (GAGs).All MPSs show an autosomal-recessive inheritance pattern except for Hunter syndrome which is an X-linked (Brusius-Facchin et al., 2014).IDS enzyme appear to be responsible for breaking down of mucopolysaccharides (also known as glycosaminoglycans).These mucopolysaccharides are components of various tissues.The breaking down of mucopolysaccharides usually occurs in the lysosomes of the cells, where cells lysosomes' containing proteins and ABSTRACT Background: Mucopolysaccharidosis type II (Hunter syndrome) an X-linked disorder mostly due to mutations in the gene responsible for production of the enzyme iduronate-2-sulfatase (IDS).It belongs to subgroup of diseases called mucopolysaccharidoses caused by accumulation of lysosomal material.It is a rare disease worldwide, having an incidence of 0.3-0.7 per 100,000 live births.Its primary cause is due to mutation affecting the IDS gene causing in accordance deficiency in the lysosomal enzyme activity.The IDS enzyme catalyzes the catabolism of glycosaminoglycans (GAGs), resulting in the accumulation of dermatan and heparan sulphates in different body tissues mainly in connective tissue, spleen, liver, and brain, with elimination of large amounts of them in the urine.The clinical spectrum can be divided into mild, intermediate, and severe variants.The patients clinically are characterized by coarsening of their facial structures, joint and bone deformities, short stature, changes in different body systems including cardiac, respiratory, ocular and olfactory systems and in severe cases troubled motor function, advanced learning complications and behavioral abnormalities can occur.To date, 792 variants have been reported by the HGMD associated with MPS type II have been identified.The study was conducted on fifteen Egyptian male patients from unrelated families with Hunter syndrome to study the molecular basis of Hunter disease among Egyptian patients through determination of iduronate 2-sulfatase gene mutations.Patients had hepatosplenomegaly, ENT problems mostly due to enlarged adenoids, central nervous system (CNS) abnormality and delayed IQ.Five novel and four previously reported mutations were detected in nine of our patients.Our study being the first Egyptian study on Hunter syndrome has shown as other studies that most mutations of MPS II appear to be unique and there is a great variety between the different populations in the presentation of the disease with different mutations