Attenuated form of type II mucopolysaccharidoses (Hunter syndrome): pitfalls and potential clues in diagnosis.

A 7-year-old boy, born of a non-consanguineous union, presented with pain over both hips and progressive difficulty in walking for preceding 2 years. He had normal developmental milestones with satisfactory scholastic performances and his family and perinatal histories were unremarkable. Clinical examination revealed short stature (height SD score (SDS): −2.3; midparental height (MPH) SDS: −1.7) with upper segment (US):lower segment (LS) ratio of 0.97, umbilical hernia, apical pansystolic murmur of mitral regurgitation and waddling gait without corneal opacity or organomegaly (figure 1). Complete blood count, baseline biochemistry and thyroid function tests were normal except presence of azurophilic granules within white blood cells seen in peripheral blood smear (figure 2). Transthoracic echocardiography confirmed moderate mitral regurgitation secondary to prolapsed posterior mitral leaflet leading to coaptation failure. Though the difference between his height centile and MPH centile was not striking, his body proportion was suggestive of short trunk dwarfism (US:LS is normally 1.4 at 1 year and 1 at 10 years of age). A whole-body skeletal survey …