A child presents at OPD with symptoms of nausea, vomiting and hypoglycaemia after eating fruit and cane sugar. The child had been breast fed, during which time these symptoms were not evident. There was some cirrhosis of the liver,
and reducing substances were present in urine. However, the glucose oxidase test was negative. Both alanine
transaminase (ALT) and aspartate transaminase (AST) levels were increased. Based on the reducing sugar present in the
urine, provide a possible diagnosis.​