GLYCOGEN STORAGE DISEASE
We recently encountered a 4-year-old boy with massive hepatomegaly (soft in consistency) and altered liver enzymes (SGOT/SGPT). Liver biopsy was suggestive of Glycogen Storage Disease (GSD) with minimal fibrosis. Genetic test showed mutation in gene encoding enzyme phosphorylase kinase confirming a diagnosis of GSD type IX.
Glycogen storage disease type IX (GSD-IX) is a group of four disorders characterized by a deficiency of the enzyme phosphorylase kinase. There is inability to break down glycogen (a complex sugar) in liver or muscle cells or sometimes both. This inability to break down glycogen interferes with the normal function of the affected tissue.
The signs and symptoms mostly begin in early childhood. The initial features are usually an enlarged liver (hepatomegaly) and slow growth. Affected children are often shorter than normal. During prolonged periods of fasting, kids may have low blood sugar and/or ketosis (elevated ketones in the blood. Diminished muscle tone (hypotonia) and muscle weakness may also be seen during early childhood. Some kids will have delayed development of motor skills, such as sitting, standing, or walking, and may have mild muscle weakness. Affected individuals may experience fatigue, muscle pain, and cramps, especially during exercise (exercise intolerance). Puberty may be delayed.
The signs and symptoms usually improve with age. Typically, individuals catch up developmentally, and adults reach normal height. However, some affected individuals develop extensive fibrosis in the liver (cirrhosis). Growth delays can be pronounced during childhood, but most children show catch-up growth and ultimately reach a normal adult height.
A diagnosis of glycogen storage disease type IX is based upon identification of characteristic symptoms, a proper patient history, a thorough clinical evaluation and relevant specialized tests including Molecular Genetic testing. Genetic testing can detect mutations in specific genes known to cause GSD-IX and is confirmatory.
Dr. Deepak Goel
Dr. Deepak Goyal, a Pediatric Gastroenterologist with extensive post-MD experience of more than 15 years that includes super-specialty training in ‘Pediatric Hepatology & Gastroenterology’ (MCI-recognized) at SGPGIMS, Lucknow, has managed various kinds of complicated Pediatric Gastroenterology, Hepatology & Liver Transplant Cases.
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