Early cardiomyopathy without severe metabolic dysregulation in a patient with cblB-type methylmalonic acidemia.

BACKGROUND: Cardiomyopathy is a known complication of organic acidemias but generally thought to be secondary to poor metabolic control. METHODS: Our patient was found through biochemical testing and Sanger sequencing to harbor an Icelandic founder mutation: NM_052845.4(MMAB):c.571C > T(p.Arg191Trp), leading to an early presentation (4 h after birth) of cblB-type methylmalonic acidemia (MMA). Biochemical testing of this patient suggested B-12-responsiveness and thus the patient was treated with cyanocobalamin throughout life. Informed parental consent was obtained for this report. RESULTS: Our patient had three metabolic decompensations in her life (at birth, at 1 month, and at 5 months). The first decompensation was probably linked to stress of delivery, second to rhinovirus infection, and third by co-infection of norovirus and enterovirus. At 3 months, the patient was noted to be tachypneic, although this was attributed to her underlying metabolic acidosis. At 5 months and 10 days, the patient was admitted with minor flu-like symptoms but developed severe diarrhea in hospital and upon rehydration had cardiac decompensation and was found to have undiagnosed dilated cardiomyopathy. Although, patient was treated aggressively with dextrose, hemodialysis, levocarnitine, and vasoactive agents, there was limited response to medications to treat cardiac failure, and eventually the patient passed away before turning 6 months old. CONCLUSIONS: Other than these three mild decompensations, patient had very good metabolic control, thus demonstrating that even without frequent metabolic decompensation, cardiomyopathy can be an observed phenotype in cblB-type MMA even very early in life, suggesting that this phenotype may be independent of metabolic control.

Living or deceased donor kidney transplantation in children.

PURPOSE OF REVIEW: Kidney transplantation is the preferred treatment modality for children with end-stage renal disease. In this review, we discuss the factors affecting the selection of the appropriate donor to ensure the best possible short and long-term outcomes. RECENT FINDINGS: Outcomes of pediatric renal transplantation from living donors are superior to those obtained from deceased donors. Despite this, the rate of living donor kidney transplantation has declined over the last decade. Living donation is considered to be safe but long-term outcomes, especially for parents who are often young donors, are not well understood. Living donation can also cause a financial impact to the donor and family. Barriers to living donation must be sought and defeated. Deceased donor organs are now the primary source of kidneys. How the risk of extended time on dialysis must be weighed against the improved outcomes that may accrue from better matching is controversial. Increasing the donor pool may be accomplished by reassessing sources that are currently avoided, such as donation after cardiac death and infant kidneys transplanted en bloc. SUMMARY: The pediatric nephrologist must balance waiting for the highest quality kidney against the need for the shortest possible waiting time.