This is a multicenter prospective non-drug screening study. The working period is 12 months. There is no research product to be followed or used in the study.

Demographic data, medical and family histories of the patients included in the study will be collected at the first admission. The following laboratory values of the patients will be collected:

• Alanine Transaminase (ALT)
• Aspartate Transaminase (AST)
• Gamma Glutamyl Transferase (GGT)
• Creatine Phosphokinase (CPK)
• In addition, physical examination information and Abdominal USG and Liver Biopsy Results, if any, will be collected. Following the above scans, enzyme analysis for late-onset Pompe disease in boys and girls and adolescents with high CPK levels and molecular genetic tests for Duchenne muscular dystrophy in boys and adolescents with high CPK levels will be performed.

Inclusion Criteria:

• 3 months -18 years old boys and girls
• Serum transaminase levels (serum ALT and / or AST levels> 1.52 upper limit of normal (ULN)) for at least 3 months
• The willingness of the patient and / or legal representative to sign the written consent form

Exclusion Criteria:

• Patients less than 3 months
• Patients with a known history of liver disease
• Patients with a known history of muscle disease
• Patients with a known history of rheumatologic disease
• Patients with clinical history or physical examination findings that support the possibility of liver disease (Jaundice, variceal bleeding, hepatomegaly, splenomegaly, ascites)
• ICU patients
• Patients with known congenital anomalies
• Patients with organ failure
• Patients with elevated serum GGT, Total Bliribun or Direct Bilirubin levels

Boys and girls with unexplained transaminase elevation for at least 3 months