title: Treatment of methylmalonic acidemia by liver or combined liver-kidney transplantation.
abstract: OBJECTIVE
  To assess biochemical, surgical, and long-term outcomes of liver (LT) or liver-kidney transplantation (LKT) for severe, early-onset methylmalonic acidemia/acid (MMA).
  
  
  METHODS
  A retrospective chart review (December 1997 to May 2012) of patients with MMA who underwent LT or LKT at Lucile Packard Children's Hospital at Stanford.
  
  
  RESULTS
  Fourteen patients underwent LT (n = 6) or LKT (n = 8) at mean age 8.2 years (range 0.8-20.7). Eleven (79%) were diagnosed during the neonatal period, including 6 by newborn screening. All underwent deceased donor transplantation; 12 (86%) received a whole liver graft. Postoperative survival was 100%. At a mean follow-up of 3.25 ± 4.2 years, patient survival was 100%, liver allograft survival 93%, and kidney allograft survival 100%. One patient underwent liver re-transplantation because of hepatic artery thrombosis. After transplantation, there were no episodes of hyperammonemia, acidosis, or metabolic decompensation. The mean serum MMA at the time of transplantation was 1648 ± 1492 μmol/L (normal <0.3, range 99-4420). By 3 days, post-transplantation levels fell on average by 87% (mean 210 ± 154 μmol/L), and at 4 months, they were 83% below pre-transplantation levels (mean 305 ± 108 μmol/L). Developmental delay was present in 12 patients (86%) before transplantation. All patients maintained neurodevelopmental abilities or exhibited improvements in motor skills, learning abilities, and social functioning.
  
  
  CONCLUSIONS
  LT or LKT for MMA eradicates episodes of hyperammonemia, results in excellent long-term survival, and suggests stabilization of neurocognitive development. Long-term follow-up is underway to evaluate whether patients who undergo early LT need kidney transplantation later in life.
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Stanford University, Stanford, CA. Electronic address: annakaisa.niemi@gmail.com.
authors.forename: Anna-Kaisa
authors.initials: AK
authors.lastname: Niemi
authors.affiliation: Division of Abdominal Transplantation, Department of Surgery, Stanford University, Stanford, CA.
authors.forename: Irene K
authors.initials: IK
authors.lastname: Kim
authors.affiliation: Division of Neonatal and Developmental Medicine, Department of Pediatrics, Stanford University, Stanford, CA.
authors.forename: Casey E
authors.initials: CE
authors.lastname: Krueger
authors.affiliation: Department of Pathology, Stanford University, Stanford, CA.
authors.forename: Tina M
authors.initials: TM
authors.lastname: Cowan
authors.affiliation: Lucile Packard Children's Hospital at Stanford, Stanford, CA.
authors.forename: Nancy
authors.initials: N
authors.lastname: Baugh
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Stanford University, Stanford, CA; Prenatal Diagnostics, Department of Obstetrics and Gynecology, University of California, San Francisco, San Francisco, CA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Farrell
authors.affiliation: Division of Abdominal Transplantation, Department of Surgery, Stanford University, Stanford, CA.
authors.forename: Clark A
authors.initials: CA
authors.lastname: Bonham
authors.affiliation: Division of Abdominal Transplantation, Department of Surgery, Stanford University, Stanford, CA.
authors.forename: Waldo
authors.initials: W
authors.lastname: Concepcion
authors.affiliation: Division of Abdominal Transplantation, Department of Surgery, Stanford University, Stanford, CA.
authors.forename: Carlos O
authors.initials: CO
authors.lastname: Esquivel
authors.affiliation: Division of Medical Genetics, Department of Pediatrics, Stanford University, Stanford, CA.
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Enns
mesh_terms: D000592:Amino Acid Metabolism, Inborn Errors / Q000601:surgery*; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016030:Kidney Transplantation; D016031:Liver Transplantation; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index