Autoimmune Diseases Web


Acid Maltase Deficiency:

Selection from: New Clinical Findings in Pompe Disease, Also Known as Acid Maltase Deficiency: Evidence-Based Cases in Infantile- and Late-Onset Patients

PompeS Disease: The Challenge of Diagnosis and Therapy


Pompe disease is a rare, progressive, often fatal metabolic disease with a wide range of clinical presentations. The most important symptoms and signs relate to cardiac and striated muscle dysfunction. The following 3 cases help delineate the sweeping spectrum of this disorder.

Patient 1

A 3-month-old infant boy is referred for evaluation of pneumonia. The child was the product of a term pregnancy born to a gravida 3, para 3 mother. Birth weight was 6 pounds. The child has been a poor feeder and has gained only 3 ounces in 3 months. His parents are concerned about paucity of movement. The mother comments that "my child just lays there like a rag doll." On examination the child is a frail-appearing infant with a respiratory rate of 50 breaths per minute. Heart rate is 150. He has moderate macroglossia. Chest examination reveals markedly decreased breath sounds over the entire left lung field. A grade 3 systolic murmur is noted. His liver is palpated 3 centimeters below the right costal margin.

Neurologically, the examination is dominated by profound global hypotonia. Head control is poor both in the prone and supine positions. When supported in vertical suspension, the infant "slips through your fingers," offering no support from his latissimus dorsi muscles. He appears profoundly weak in both proximal and distal muscles. He is hyporeflexic but not areflexic. Chest x-ray reveals marked cardiomegaly. Routine laboratory work is unremarkable, with the exception of a creatine kinase (CK) level of 820 IU.

Patient 2

A 42-year-old woman complains of a history of 10 years of global fatigue and leg weakness. She was previously athletic and ran marathons until she was 32 years of age. At age 34, she noted difficulty carrying her 30-pound toddler up a flight of stairs. A progressive decline in her exercise training ensued over 2 years. Eight-minute miles became 20-minute slow jogs. She complains of difficulty climbing up stairs and getting out of low chairs.

In retrospect, she states she has never been able to do a sit up. She has seen multiple physicians in the past, none of whom unearthed abnormalities on her physical examination. Elevated liver function studies (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) prompted additional testing. The results of the hepatitis panel were negative, and liver biopsy was unremarkable. Over the past 2 years, she has seen specialists including an endocrinologist and psychiatrist. She was seen by a rheumatologist, who obtained an elevated CK level of 560 IU. A presumptive diagnosis of polymyositis was made, but no clinical improvement followed a 3-month trial of prednisone. Her examination now revealed a well-developed anxious woman. She walked with a wide base, moderately hyperlordotic gate. She had great difficulties with stoop and recovery. To rise from the chair, she needed to lean forward and stabilize her upper body by placing her hands on her knees. She had mild weakness of her deltoids and more obvious weakness of hip flexors, the extensors, and hip abductors. A tentative diagnosis of limb girdle muscular dystrophy was made. A muscle biopsy of the vastus lateralis revealed vacuolated fibers. Glycogen stains (periodic acid-Schiff) revealed marked increase in glycogen level. Electron microscopy confirmed that granules were contained in membrane-bound structures consistent with lysosomal glycogen accumulation.

Patient 3

A 37-year-old man is referred for evaluation of frequent headaches. For the past year, he has had nearly daily morning headaches. Over the past 6 months, he has noted difficulty initiating or sustaining sleep. He frequently wakes at night because of "nightmares." His wife is concerned about his global feeling of fatigue. he notes that his posture has changed over the past several years giving him a "swayback appearance."

His examination reveals a thin, poorly muscled gentleman. His chest reveals diminished breath sounds in both bases. He is only able to count to 24 on a single breath. When standing, he exhibits moderate hyperlordosis. With his arms extended, he has protrusion of both shoulder blades typical of scapular winging. He is unable to rise from a seated position on the floor.

His neurologic examination show subtle weakness in his deltoids and external shoulder rotators. His hip flexors, hip extensors, and thigh abductors are weak. His deep tendon reflexes reveal absent knee jerks. Pulmonary function studies reveal a seated vital capacity (VC) of 1.4 liters but a supine VC of only .6 liters.