Little clinical difference exists between these four types but symptoms appear most severe and seem to progress more quickly in children with type A. The average duration of Sanfilippo syndrome is 8 to 10 years following onset of symptoms. Most persons with MPS III live into their teenage years, and some live longer. Sanfilippo A is the most severe of the MPS III disorders and is caused by the missing or altered enzyme heparan N-sulfatase. Children with Sanfilippo A have the shortest survival rate among those with the MPS III disorders. Sanfilippo B is caused by the missing or deficient enzyme alpha-N-acetylglucosaminidase. Sanfilippo C results from the missing or altered enzyme acetyl-CoAlpha-glucosaminide acetyltransferase. Sanfilippo D is caused by the missing or deficient enzyme N-acetylglucosamine 6-sulfatase.The incidence of Sanfilippo syndrome (for all four types combined) is about one in 70,000 births. MPS IV
MPS IV, Morquio syndrome, is estimated to occur in 1 in 700,000 births. Its two subtypes result from the missing or deficient enzymes N-acetylgalactosamine-6-sulfatase (GALNS) (Type A) or beta-galactosidase (Type B) needed to break down the keratan sulfate sugar chain. Clinical features are similar in both types but appear milder in Morquio Type B. Onset is between ages 1 and 3. Neurological complications include spinal nerve and nerve root compression resulting from extreme, progressive skeletal changes, particularly in the ribs and chest; conductive and/or neurosensitive loss of hearing and clouded corneas. Intelligence is normal unless hydrocephalus develops and is not treated.
Oxygen is often required to resolve the shortness of breath. Additionally, oxygen to the lungs also helps relax the blood vessels and eases right heart failure. When wheezing is present, the majority of individuals require a bronchodilator. A variety of medications have been developed to relax the blood vessels in the lung, calcium channel blockers are used but only work in few cases and according to NICE are not recommended for use at all.Anticoagulants are used when venous thromboembolism is present. Venesection is used in severe secondary polycythemia (because of hypoxia), which improves symptoms though survival rate has not been proven to increase. Finally, transplantation of single/double lung in extreme cases of cor pulmonale is also an option. Epidemiology
The epidemiology of pulmonary heart disease (cor pulmonale) accounts for 7% of all heart disease in the U.S According to Weitzenblum, et al., the mortality that is related to cor pulmonale is not easy to ascertain, as it is a complication of COPD. See also
Bilharzial cor pulmonale. References
Further reading
Forfia, Paul R.; Vaidya, Anjali; Wiegers, Susan E. (2013-01-01). "Pulmonary heart disease: The heart-lung interaction and its impact on patient phenotypes". Pulmonary Circulation. 3 (1): 5–19. doi:10.4103/2045-8932.109910. ISSN 2045-8932. PMC 3641739. PMID 23662171. Taussig, Lynn M.; Landau, Louis I. (2008-04-09). Pediatric Respiratory Medicine. Elsevier Health Sciences. ISBN 978-0323070720. Jamal, K.; Fleetham, J. A.; Thurlbeck, W. M. (1990-05-01). "Cor Pulmonale: Correlation with Central Airway Lesions, Peripheral Airway Lesions, Emphysema, and Control of Breathing". American Review of Respiratory Disease. 141 (5_pt_1): 1172–1177. doi:10.1164/ajrccm/141.5_Pt_1.1172. ISSN 0003-0805. PMID 2339840. == External links ==