Background Morbidity remains high in MMAmut0 patients. Liver transplantation can decrease metabolic decompensation episodes and organ damage whilst improving quality of life (QOL).

Case report An infant was prospectively managed as family history of MMAmut0, and confirmed postnatally. Bilateral dysplastic multicystic kidneys were diagnosed after birth and hepatoblastoma at 4 months. He underwent liver transplant age 6 months for tumour removal and MMA management.

Pre-transplant Due to low albumin (<20 g/L), poor weight gain (0.4th-2nd to < 0.4th centile), protein was increased, 2 to 2.4 g/kg/d (WHO 2007, safe intake (SI) 1.77 g/kg/d), energy 120 to 140kcal/kg/d. He fed orally with NG top-ups. Poor feed tolerance necessitated a hydrolysed feed. Parenteral nutrition (PN) was required twice because of vomiting. Age 12 weeks protein was decreased, 1.85 g/kg/d as ammonia remained high (120-148umol/L). He thrived (weight, length 25th -50thcentile). Median plasma MMA (pMMA) was 134umol/L (range 44.2-230), (ref range 0-0.29).

Post-transplant PN matched pre-transplant protein and energy intakes. He recommenced hydrolysed feed, via NGT and orally. After 3 months pMMA remained elevated, median 125umol/L (range 76.9- 169) protein was reduced to 1.5 g/kg/d (SI 1.14 g/kg/d) and is unchanged 1year post-transplant. All feeds are taken orally.

Conclusion Episodes of metabolic decompensation markedly decreased. Parents report QOL improved. Protein remains restricted.