Mucolipidosis II (ML II) is a particularly severe form of ML that has a significant resemblance to another mucopolysaccharidosis called Hurler syndrome. Generally only laboratory testing can distinguish the two as the presentation is so similar, with high plasma concentrations of lysosomal enzymes, often fatal in childhood. Typically, by the age of 6 months, failure to thrive and developmental delays are obvious signs of this disorder. Some physical signs, such as abnormal skeletal development, coarse facial features, and restricted joint movement, may be present at birth. Children with ML II usually have enlargement of certain organs, such as the liver (hepatomegaly) or spleen (splenomegaly), and sometimes even the heart valves. Affected children often have stiff claw-shaped hands and fail to grow and develop in the first months of life. Delays in the development of their motor skills are usually more pronounced than delays in their cognitive (mental processing) skills. Children with ML II eventually develop a clouding on the cornea of their eyes and, because of their lack of growth, develop short-trunk dwarfism (underdeveloped trunk). These young patients are often plagued by recurrent respiratory tract infections, including pneumonia, otitis media (middle ear infections), bronchitis and carpal tunnel syndrome. Children with ML II generally die before their seventh year of life, often as a result of congestive heart failure or recurrent respiratory tract infections.
I-cell disease
Anti-IgLON5 disease
Hyper IgM syndrome
CD25 deficiency
Hyper-IgM syndrome type 1
Hyper-IgM syndrome type 2
Hyper-IgM syndrome type 4
Hyper-IgM syndrome type 5