A NOVEL MUTATION OF THE GAA GENE IN A FINNISH LATE-ONSET POMPE DISEASE PATIENT: CLINICAL PHENOTYPE AND FOLLOW-UP WITH ENZYME REPLACEMENT THERAPY

Pompe disease is a rare, progressive disease leading to skeletal muscle weakness due to deficiency of the acid alpha-glucosidase (GAA) enzyme. Herein we report the first diagnosed Finnish patient with a phenotype compatible with the late-onset form of Pompe disease. Molecular genetic analysis of the GAA gene revealed a novel missense mutation, 1725C>A (YS75X), combined with a previously reported mutation, 1634C>T (P545L). Human recombinant a-glucosidase enzyme (alglucosiclase-alpha) treatment was initiated for this patient at age 20 years. After 12 months she was no longer fully wheelchair-bound, and muscle strength had improved. No disease progression was visible on muscle magnetic resonance imaging of the lower limbs, and the energy state of the muscle cells increased by 46% on phosphorus magnetic resonance spectroscopy. Overall, our findings suggest that enzyme replacement therapy is indicated, even in patients with late-onset Pompe disease, to halt disease progression and improve the quality of daily life. Muscle Nerve 40: 143-148, 2009