Morquio syndrome

Alternative names

Mucopolysaccharidosis type IVA (galactosamine-6-sulfatase deficiency); Mucopolysaccharidosis type IVB (beta galactosidase deficiency)

Definition

Morquio syndrome is an inherited disease belonging to the group of Mucopolysaccharide storage diseases. Two forms are recognized, type A and type B.

Type A disease is characterized by the absence of the enzyme galactosamine-6-sulfatase, and the excretion of keratan sulfate in the urine. Type B disease results from deficiency of the enzyme beta galactosidase.
In both types there is accumulation in the body and brain of abnormally large amounts of a substance called Mucopolysaccharide.

Causes, incidence, and risk factors

Morquio syndrome is transmitted as an autosomal recessive trait. It has several symptoms in common with other mucopolysaccharide storage diseases such as coarse facial features, short stature, and skeletal and joint abnormalities.

Like Sanfilippo syndrome, onset of symptoms is delayed until after the first year, and life expectancy may exceed 20 years. Unlike Sanfilippo syndrome, the mental development is often normal.

Symptoms

• Family history of Morquio syndrome
  
• Coarse facial features (more mild than either Hunter syndrome or Hurler syndrome)
  
• Large head (macrocephaly)
  
• Knock-knees
  
• Widely spaced teeth
  
• Bell-shaped chest with ribs flared out at the bottom
  
• Short stature with a particularly short trunk
  
• Hypermobile joints
  
• Abnormal development of many bones including the spine
  
• Compression of the spinal cord can lead to weakness or paralysis
  

Signs and tests

Physical examination and testing shows:

• Cloudy cornea
  
• Liver enlargement
  
• Inguinal hernias
  
• Kyphoscoliosis (abnormal curvature of the spine)
  
• Short stature (especially short trunk)