Morquio A: Endurance

Endurance testing assesses functional capacity

Endurance tests measure the efficiency of performing a task and provide assessments of:

Functional status of the cardiac, respiratory and musculoskeletal systemsOverall disease progressionQuality of lifeResponse to treatments

McDonald et al, J Pediatr Rehabil Med, 2010; Hendriksz et al, J Inherit Metab Dis, 2012

Image courtesy of Elizabeth Wright

Recommended endurance tests for assessing submaximal functional capacity in Morquio A patients include:

6 minute walk test (6MWT)measures how far a person can walk on a hard, flat surface in 6 minutes a standardized test (American Thoracic Society, 2002)used to assess endurance in patients with MPS VI (Harmatz et al, 2005) and Morquio A (Harmatz et al, 2013)

3 minute stair climb (3MSCT) measures how many steps a person can ascend in 3 minutes, using rails and resting as neededused to assess endurance in patients with MPS VI (Harmatz et al, 2005) and Morquio A (Harmatz et al, 2013)

Harmatz et al, Mol Genet Metab, 2013; Harmatz et al, Pediatrics, 2005; McDonald et al, J Pediatr Rehabil Med, 2010;

Hendriksz et al, J Inherit Metab Dis, 2012

Submaximal intensity tests are sensitive indicators of endurance for MPS patients

Endurance is impaired in Morquio A

Mean 6MWT = 212.6 ±152.2 m (n = 316 subjects)

Mean 3MSCT = 30.0 ±24.0 stairs (n= 274 subjects)

Harmatz et al, Mol Genet Metab, 2013MorCAP baseline data

Mean 6MWT Mean 3MSCT

n=248 n=68 n=316 n=215 n=59 n=274Age ≤ 18 years Age > 18 years All

180

185

190

195

200

205

210

215

220 218

193.1

212.6

m

Age ≤ 18 years Age > 18 years All 0

5

10

15

20

25

30

3531.6

24.1

30

Ste

ps/m

in

Assessment At diagnosis Annually As clinically

indicated

Evaluation by physiotherapist X X X

6 MWT (if physically and developmentally able) X X X

3 MSCT (if physically and developmentally able) X X X

Regular assessments are recommended for optimal patient quality of life

Hendriksz et al, J Inherit Metab Dis, 2012