Floppy baby syndrome is a common diagnostic problem in newborns and infants. This condition is associated with impaired development of motor skills, hypotonia, profound weakness, and rag-doll features. As these symptoms can be found in numerous disorders, the diagnosis of the underlying cause of floppy baby syndrome can be complex and problematic. For effective management of these infants, it is critical that all potential causes are examined as early in the course of disease as possible. Pompe disease is a rare, progressive, and often fatal muscular disease. The underlying pathology is a deficiency of the enzyme acid alpha-glucosidase (GAA) that hydrolyzes lysosomal glycogen. Pompe disease is a single disease with a wide spectrum of clinical signs, which vary in term of age of onset, rate of disease progression, and extent of organ involvement. Pompe disease is an uncommon cause of floppy baby syndrome and, therefore, often overlooked in early differential diagnosis in infants. The accurate diagnosis of floppy baby syndrome requires the sequential evaluation of the central nervous system, neuromuscular tissue, connective tissue, and possible endocrinologic, chromosomal, genetic and metabolic disorders. Paediatricians should focus on Pompe disease particularly when a chest x-ray shows evidence of enlarged heart and electrocardiography shows a short P-R interval. Based on these findings, further work-up or referral to a specialist can be considered, as Pompe disease requires immediate attention. Enzyme replacement therapy can lead to a significant motor and respiratory improvement in patients who start the therapy before extensive muscle damage has occurred. Early diagnosis is critical, because enzyme replacement therapies under investigation may allow for the treatment of the disorder, particularly before the changes in muscles become irreversible

Key words:
drug therapy; GAA protein, human; glycogen storage disease type II; infant, newborn; muscle hypotonia