Toward deconstructing the phenotype of late-onset Pompe disease.
ABSTRACT Pompe disease (glycogen storage disease type 2 or acid maltase deficiency) is a rare autosomal recessive lysosomal storage disorder. Since the advent of ERT a lot has been learned about the phenotypic spectrum especially in the late onset patients. We describe in detail 44 patients diagnosed with late-onset Pompe disease (LOPD) at our neuromuscular department from 1985 to 2011 and compare them to patients with LOPD in the literature of the past 40 years. Study of the Munich LOPD group revealed varying musculoskeletal and cardio-cerebrovascular manifestation patterns. Several of these symptom patterns commonly appeared in conjunction with one another, highlighting the multisystem involvement of this condition. Common symptom patterns include: (i) Classic limb girdle and diaphragmatic weakness, (ii) rigid spine syndrome (RSS), scoliosis, and low body mass, and (iii) several cardio-cerebrovascular manifestation patterns. The most common presentation, limb girdle and diaphragmatic weakness, appeared in 78% (34/44) of our patients and over 80% of those in the literature. Sixteen percent (7/44) of our patients presented with rigid spine, scoliosis, and low body mass. Although scoliosis had a reported frequency of 33% in the general LOPD patient population, the literature only occasionally reported low body mass and RSS. Importantly, a multisystem extramuscular finding accompanied by cardio-cerebrovascular manifestations was found in 29% (13/44) of our LOPD patients; the literature showed an increasing prevalence of this latter finding. By examining the phenotype of patients with confirmed LOPD, we found a more subtle clinical multisystem involvement in LOPD. Whether patients presenting with the different symptom patterns respond differently to enzyme replacement therapy remains a key question for future research. © 2012 Wiley Periodicals, Inc.
Article: Clinical features and predictors for disease natural progression in adults with Pompe disease: a nationwide prospective observational study.[show abstract] [hide abstract]
ABSTRACT: BACKGROUND: Due partly to physicians' unawareness, many adults with Pompe disease are diagnosed with great delay. Besides, it is not well known which factors influence the rate of disease progression, and thus disease outcome. We delineated the specific clinical features of Pompe disease in adults, and mapped out the distribution and severity of muscle weakness, and the sequence of involvement of the individual muscle groups. Furthermore, we defined the natural disease course and identified prognostic factors for disease progression. METHODS: We conducted a single-center, prospective, observational study. Muscle strength (manual muscle testing, and hand-held dynamometry), muscle function (quick motor function test), and pulmonary function (forced vital capacity in sitting and supine positions) were assessed every 3--6 months and analyzed using repeated-measures ANOVA. RESULTS: Between October 2004 and August 2009, 94 patients aged between 25 and 75 years were included in the study. Although skeletal muscle weakness was typically distributed in a limb-girdle pattern, many patients had unfamiliar features such as ptosis (23%), bulbar weakness (28%), and scapular winging (33%). During follow-up (average 1.6 years, range 0.5-4.2 years), skeletal muscle strength deteriorated significantly (mean declines of -1.3% point/year for manual muscle testing and of -2.6% points/year for hand-held dynamometry; both p<0.001). Longer disease duration (>15 years) and pulmonary involvement (forced vital capacity in sitting position <80%) at study entry predicted faster decline. On average, forced vital capacity in supine position deteriorated by 1.3% points per year (p=0.02). Decline in pulmonary function was consistent across subgroups. Ten percent of patients declined unexpectedly fast. CONCLUSIONS: Recognizing patterns of common and less familiar characteristics in adults with Pompe disease facilitates timely diagnosis. Longer disease duration and reduced pulmonary function stand out as predictors of rapid disease progression, and aid in deciding whether to initiate enzyme replacement therapy, or when.Orphanet Journal of Rare Diseases 11/2012; 7(1):88. · 5.83 Impact Factor