(Mucopolysaccharidosis type VI)

Very rare. Autosomal recessive transmission (chromosome 5q13-q14). Qualitative or quantitative deficiency in arylsulfatase B (or N-acetylgalactosamine-4-sulfatase) that results in an accumulation of dermatan-sulfate degradation products in the lysosomes of all cells. This accumulation leads to cell and tissue damage. The disease is clinically manifest if the enzyme activity is less than 10% of normal.

The symptomatology is heterogeneous but generally very similar to Hurler disease (mucopolysaccharidosis type I): 

-         facial dysmorphism: macroglossia, gingival hyperplasia, maxillary hypoplasia, badly positioned teeth

-          obstructive sleep apnea occasionally resulting in chronic pulmonary heart; a tracheostomy is sometimes needed (with or without a Montgomery tube)

-         ENT: chronic purulent rhinitis, enlarged tonsils and adenoids, thickening of the epiglottis and the vocal cords, narrow trachea

-         hepatosplenomegaly 

-         multiple dysostoses: C1 - C2 instability, malformation of the dorso-lumbar vertebrae with risk of spinal cord compression,  short and irregular clavicles; deformation of the hands, carpal tunnel; early hip arthrosis (dysplasia of the femoral head or coxa valga)

-         heart disease due to the accumulation of degradation products and to the nighttime hypoxemia: mitral  and/or aortic valvulopathy (regurgitation > > stenosis); rare cardiomyopathy; coronary involvement to be excluded

-         deafness

-         corneal opacities, glaucoma

-         intracranial hypertension by thickening of the dura mater and dysfunction of arachnoid villi 

Intelligence is usually normal.

Treatment: other than the specific treatment of complications; a partially curative treatment consists of

-         transplantation of bone marrow or stem cells (umbilical cord) 

-         or enzymatic treatment: galsulfase at a dose of 1 mg/kg IV in 4 h once a week.

Enzymatic treatment causes a decrease of septal hypertrophy and stabilization of lesions of the mitral and aortic valves if the treatment is started before the age of 12 years. 

Anesthetic implications: 

major anesthetic risk. Preoperative echocardiography: check mitral and aortic valves. Check the hemostasis: dermatan sulfate in blood can possibly interfere with heparin cofactor II. Risk of difficult intubation and ventilation: if fiberoptic intubation is planned, be aware that the inside of the trachea can be mistakenly taken for esophagus due to mucosal infiltration (be sure to spot the carina !). C1 - C2 instability. Obstructive apnea: use a nasopharyngeal (but risk of epistaxis) rather than oralpharyngeal airway.

References : 

• Giugliani R, Harmatz P, Wraith JE. 
  Management guidelines for mucopolysaccharidosis VI. 
  Pediatrics 2007; 120: 405-18
• Braunlin E, Rosenfeld H, Kampmann C et al. 
  Enzyme replacement therapy for mucopolysaccharidosis VI: long-term cardiac effects of galsulfase (Naglazyme®) therapy. 
  J Inherit Metab Dis 2012; online 5-6-2012
• Cade J, Jansen N.
  Anesthetic challenges in an adult with mucopolysaccharidosis type VI.
  A & A Case Reports 2014 ; 2 : 152-4

Updated: December  2016