Inborn Errors of Metabolism

Inborn errors of metabolism (IEMs) are a group of genetic disorders characterized by biochemical function abnormalities. Early diagnosis leads to early initiation of treatment and a significant decrease in morbidity and mortality. Infants and toddlers with inborn errors of metabolism may be candidates for hematopoietic stem cell transplantation (HSCT), which when conditioned with total body irradiation and gonadotoxic medications often results in infertility. Fertility preservation options should be discussed with families prior to initiation of HSCT with special consideration of the hereditary nature of each condition and the possible disease-related impaired cognitive outcome. This chapter reviews the known inborn errors of metabolism that are current candidates for HSCT. Please note that galactosemia is discussed in detail in Chapter 6, and gonadal failure is secondary to disease in galactosemia, rather than treatment.