Novel IDS Variants Identified in Three Unrelated Pakistani Patients Affected with Mucopolysaccharidosis Type II (Hunter Syndrome).

Introduction: Mucopolysaccharidosis type II (MPS-II) or Hunter syndrome is a rare X-linked recessive disorder caused by genetic lesions in the IDS gene, encoding the iduronate-2-sulfatase (IDS) enzyme, disrupting the metabolism of certain sulfate components of the extracellular matrix. Thus, the undegraded components, also known as glycosaminoglycans, accumulate in multiple tissues resulting in multisystemic abnormalities.

Objective: To uncover causative genetic lesions in probands of three unrelated Pakistani families affected with rare X-linked recessive Hunter syndrome.

Genetic testing of two Pakistani patients affected with rare autosomal recessive Fanconi-Bickel syndrome and identification of a novel SLC2A2 splice site variant.

Fanconi-Bickel syndrome (FBS) is a rare autosomal recessive carbohydrate metabolism disorder caused by mutations in SLC2A2 encoding the glucose transporter 2 (GLUT2) protein. The clinical manifestations include hepatomegaly, conditional hypo/hyperglycemia, rickets, short stature and proximal renal tubular dysfunction. GLUT2 regulates monosaccharide homeostasis through sugar sensing and transmembrane transportation during high/low glucose levels.