Dear Editor:Maple syrup urine disease (MSUD), an inherited autosomal recessive disorder of branched-chain amino acid metabolism, is characterized by potentially life-threatening episodes of ketoacidosis. 1,2 Leucine, isoleucine, and valine also are neurotoxic, and longterm high levels can produce different grades of neurologic impairment if the disease is not treated. 3 Patients would need to follow a special diet with exclusion of branched amino acids their entire life. The failure to control diet leads to the development of deficits, and the urine's particular aspect, which leads to the name of the disease. Aside from early control of diet, another therapy could be a liver transplant, which provides enough volume of enzymes, offering the patient a chance of a normal diet and the ability to stop progression of the disease. While the liver has otherwise normal functioning, the concept of transplanting MSUD patient's liver, as a domino liver transplant, to a patient without the disease, where the muscles and kidney cover the metabolic needs, becomes a reality in practice. Herein, we report the first case of a domino liver transplant done in Saudi Arabia for MSUD.A 12-year-old, 33 kg patient, with MSUD was evaluated, and a liver transplant was indicated, planning to use his native liver as a domino liver transplant. He was diagnosed as having MSUD since birth, with a history of seizures and encephalitis 40 days after birth. He developed fine and gross motor dysfunction. He had good brain function, good performance in practical reasoning, speech, and language; however, there was a delay in his personal skills, hand coordination, and performance skills owing to spasticity in his hands. The second recipient was a 55-year-old, 61-kg female patient with HCV cirrhosis and HCC under Milan criteria, after transarterial chemoembolization. A 6-year-old brain dead donor secondary to a head trauma, with a body weight of 20 kg became available, and the decision to proceed with the transplant was taken. After recovering the 380-gram liver graft has a replaced right hepatic artery coming from the superior mesenteric artery, so the proximal abdominal and the thoracic aorta were recovered en bloc with the celiac and the superior mesenteric artery. The child with MSUD had a hepatectomy, which was done with the preservation of the native inferior vena cava, and the transplant was performed in a piggyback fashion. The portal vein was anastomosed end-to-end, and the arterial supply was re-established using the thoracic aorta of the donor as a jump graft to infrarenal aorta. The biliary anastomosis was ductto-duct. The second recipient received a modified piggyback technique. The graft weight was 564 grams, and it had 2 arteries-the right and a replaced left, originating from left gastric artery. Portal vein anastomosis was also done end-to-end. The arterial anastomoses were done under a microscope using the native right and left hepatic arterial stumps. The biliary anastomosis was duct-to-duct.The pediatric recipient was extubated on ...