A case of jaundice with 50% direct bilirubin, other LFTs normal. Diagnosis is –
Rotor syndrome
Gilbert syndrome
Glucuronyl transferase deficiency
Primary biliary cirrhosis
50% direct bilirubin means conjugated hyperbilirubinemia.
Normally the direct (conjugated) bilirubin is less than 15-20% of total bilirubin.

Normal Values of bilirubin
Total bilirubin       >             0.2 - 1.9 mg/d1.
    Direct bilirubin >             0 - 0.3 mg/dl.

So, this child has : -


Conjugated hyperbilirubinemia
Other LFTs normal


Amongst the given options, Rotor syndrome and Primary biliary cirrhosis cause conjugated hyperbilirubinemia.
In Primary biliary cirrhosis, other LFTs are also abnormal, e.g., SGOT and SGPT are raised. Now we are left with Rotor syndrome which causes conjugated hyperbilirubinemia. Other LFTs are normal.