PURPOSE: Floppy infant, or congenital hypotonia, is caused by various diseases, such as genomic disorders, diseases involving the central or peripheral nervous system, musculoskeletal diseases, and metabolic disorders. We describe here the clinical aspects and the final diagnosis of infants with hypotonia recently diagnosed in a single, tertiary-care hospital in Korea. METHODS: All of the infants evaluated for generalized hypotonia between 2008 and 2012 at Asan Medical Center Children's Hospital were included in our study. The demographic data, physical examination upon initial presentation, the diagnostic tests and results, and the final diagnosis were retrospectively reviewed. RESULTS: A total of 128 infants (68 males, 60 females) were included in the study, and the mean patient age at the time of the diagnosis of hypotonia was 4.8 months. Etiological diagnosis was possible in 80 (62.5%) of the 128 patients, and 57 (44.5%) patients were confirmed by genetic testing. Fifteen patients (11.7%) were categorized as having central nervous system disorders, and 34 (26.6%) patients were diagnosed as having other genomic disorders such as Prader-Willi syndrome (n=17). Disease involving muscle and the peripheral nervous system was detected in 16 (12.5%) patients. Five patients were diagnosed with other skeletal disorders, and metabolic disease was detected in 10 (7.8%) patients. CONCLUSION: With the recent advances in diagnostic tools, including genetic testing, many of the patients with hypotonia can be correctly diagnosed. These data can give practical clues regarding the optimal diagnostic approaches for treating floppy infants in the clinics.
Central Nervous System Diseases ; Chungcheongnam-do ; Diagnosis ; Diagnostic Tests, Routine ; Genetic Testing ; Genetics ; Humans ; Infant* ; Korea ; Male ; Metabolic Diseases ; Muscle Hypotonia ; Musculoskeletal Diseases ; Peripheral Nervous System ; Physical Examination ; Prader-Willi Syndrome ; Retrospective Studies