Diagnosis Is Often Delayed: Refer at First Suspicion of MPS VI

It is critical to diagnose MPS VI and other lysosomal storage disorders (LSDs) as early as possible, before irreversible complications occur.¹

Unfortunately, although symptoms often emerge during the first few years of life, diagnosis is frequently delayed. The initial symptoms of MPS VI may be subtle, especially in patients with slowly advancing disease. Furthermore, initial signs and symptoms are often the same as common pediatric complaints, such as recurrent otitis media, recurrent sinopulmonary infections, slow growth, and umbilical or inguinal hernia. Another factor contributing to delayed diagnosis is that most physicians have not seen an MPS VI patient and are unfamiliar with the disease.^2,3

In a survey study of patients with a closely related LSD (MPS I), the presence of MPS was not suspected for an average of 2.5 years after initial presentation of symptoms; during that time, multiple specialists were seen. For individuals with slowly advancing disease, an accurate diagnosis may occur even later—well into adolescence or adulthood.^3,4

MPS VI is progressive and often leads to significant disability and a shortened life span. While there is no cure for MPS VI, the need for early diagnosis is urgent as proactive assessment and appropriate intervention can impact some of the most debilitating sequelae associated with MPS VI complications, such as blindness secondary to hydrocephalus or paralysis secondary to spinal cord compression. Without proactive care, some pathologies, such as cardiac valve disease, may progress silently for many years.^1,2

Now, with the availability of enzyme replacement therapy (ERT) in some countries, the importance of early diagnosis is increased.  Enzyme replacement therapy for MPS VI has been shown to reduce levels of urinary GAG.

It is most important to diagnose MPS VI patients at an early stage of the disease. This would allow multidisciplinary clinical management to begin earlier, while potentially devastating sequelae, such as blindness secondary to hydrocephalus, can still be prevented.

MPS VI Diagnosis Pathway

The algorithm below displays the typical diagnostic pathway for a patient with MPS VI.

1. Wilcox WR. Lysosomal storage disorders: the need for better pediatric recognition and comprehensive care. J Pediatr. 2004;144(5 Suppl):S3-S14. Review.
2. Neufeld EF, Muenzer J. The mucopolysaccharidoses. In: Scriver CR, Beaudet AL, Sly WS, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. Vol 3. 8th ed. New York, NY: McGraw- Hill; 2001:3421-3452.
3. Paterson DE, Harper G, Weston HJ, Mattingley J. Maroteaux-Lamy syndrome, mild form—MPS vi b. Br J Radiol. 1982;55:805-812.
4. MPS I survey results: patterns in the referral, diagnosis, and management of individuals with MPS I. National MPS Society and Genzyme Corporation. April 2004. Available at: http://www.mpssociety.org/content/4010/Library/.