AMPD1 Genotypes and Exercise Capacity in McArdle Patients

The purpose of this study was to assess if there exists an association between C34T muscle adenosine monophosphate deaminase ( AMPD1) genotypes (i.e., normal homyzygotes [CC] vs. heterozygotes [ CT]) and directly measured indices of exercise capacity (peak oxygen uptake [VO(2peak)], ventilatory threshold [VT], gross mechanical efficiency [GE], etc.) in 44 Caucasian McArdle patients (23 males, 21 females). All patients performed a graded cycle ergometer test until exhaustion (for VO(2peak) and VT determination) and a 12-min constant-load test at the power output eliciting the VT (for GE determination). We found no significant difference in indices of exercise capacity between CC (n = 18) and CT genotypes (n = 5) in the group of male patients (p > 0.05). In contrast, the VO(2) at the VT was significantly lower (p < 0.05) in CT (n = 4; 7.9 +/- 0.4 ml/kg/min) than in CC female patients (n = 17; 11.0 +/- 0.9 ml/kg/min). In summary, heterozigosity for the C34T allele of the AMPD gene is associated with reduced submaximal aerobic capacity in female patients with McArdle disease and might partly account, in this gender, for the variability that exists in the phenotypic manifestation of the disease.

Functional Capacity of Children with Leukemia

The purpose of this study was to determine if the functional capacity and quality of life of children receiving treatment against acute lymphoblastic leukemia (ALL) is decreased compared to healthy age and gender-matched children. Functional capacity was assessed with a number of measurements as the peak oxygen uptake (VO2peak) and ventilatory threshold determined during a ramp treadmill test, functional mobility (Timed Up and Down Stairs test [TUDS]) and ankle dorsiflexion passive and active range of motion (passive and active DF-ROM, respectively). Quality of life (QOL) was determined with the Spanish version of the Child Report Form of the Child Health and Illness Profile-Child Edition (CHIP-CE/CRF). Fifteen children (9 boys, 6 girls; mean [SD] age: 6.8 +/- 3.1 years) receiving maintenance therapy against ALL were studied and fifteen, nonathletic healthy children (9 boys, 6 girls; 6.9 +/- 3.3 years) were selected as controls. The mean values of VO2peak and active DF-ROM were significantly (p < 0.05) lower in patients (25.3 +/- 6.5 ml . kg (-1) . min (-1) vs. 31.9 +/- 6.8 ml . kg (-1) . min (-1) in controls and 19.6 +/- 8.0 degrees vs. 24.1 +/- 5.0 degrees , respectively). Children's self report of satisfaction (with self and health) (p < 0.05), comfort (concerning emotional and physical symptoms and limitations) (p < 0.01) and resilience (positive activities that promote health) (p < 0.01) were significantly decreased in patients with ALL. In summary, children receiving treatment against ALL have overall lower functional capacity and QOL than healthy children. However, their physical condition and health status are sufficiently high to allow them to participate in physical activities and supervised exercise programs.

Benefits of intrahospital exercise training after pediatric bone marrow transplantation

The purpose of this study was to determine if an eight-week intrahospital supervised, conditioning program improves functional capacity and quality of life (QOL) in children (4 boys, 4 girls) (mean [SD] age: 10.9 [2.8] years [range: 8-16]) who have undergone bone marrow transplantation (BMT) for leukemia treatment within the last 12 months. A group of 8 age and gender-matched healthy children served as controls. The experimental group performed 3 weekly sessions of resistance and aerobic training inside an intra-hospital gymnasium. A significant combined effect of group and time (p < 0.05) was observed for muscle functional capacity (Timed Up and Down Stairs [TUDS] test) and peak oxygen uptake (V.O(2peak)), i.e., with BMT children showing greater improvements than controls (V.O(2peak) at pre- and post-training of 25.9 (8.2) and 31.1 (7.6) mL/kg/min in diseased children). Muscle strength (6 RM test for bench and leg press and seated row) also improved after training (p < 0.05) in the BMT group. Concerning QOL, a significant combined effect of group and time (p < 0.05) was also observed for children's self-report of comfort and resilience and for parents' report of their children's satisfaction and achievement. In summary, children who have received BMT experience physical and overall health benefits after a relatively short-term (8 weeks) supervised exercise training program.

The I allele of the ACE gene is associated with improved exercise capacity in women with McArdle disease

BACKGROUND

McArdle disease is an uncommon metabolic disorder usually characterized by marked exercise intolerance although great individual variability exists in its phenotypic manifestation.

OBJECTIVE

The purpose of this study was to determine the association between angiotensin-converting enzyme (ACE) genotypes and indices of exercise capacity (peak oxygen uptake (VO(2)peak), ventilatory threshold (VT) and gross mechanical efficiency (GE)) in patients with McArdle disease. Based on previous research, it was hypothesized that the I allele might favourably influence exercise capacity.

METHODS

Forty-four Spanish patients (23 males, 21 females) and 44 age-matched and gender-matched controls (23 males, 21 females) performed a graded cycle-ergometer test until exhaustion (for VO(2)peak and VT determination) and a 12 min constant-load test at the power output eliciting the VT (for GE determination).

RESULTS

No significant difference (p>0.05) was found in indices of exercise capacity between ID + II genotypes and DD homozygotes in the group of male patients, male controls and female controls. However, in the group of female patients, the ID + II group (n = 11) had a higher VO(2)peak than DD homozygotes (n = 10) (15.8 (SEM 1.6) ml/kg/min versus 11.9 (SEM 0.9) ml/kg/min, respectively; p<0.05).

CONCLUSIONS

The I allele of the ACE gene is associated with a higher functional capacity in female patients, and might partly explain the individual variability in the phenotypic manifestation of McArdle disease.