International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which condition allows for limited breastfeeding due to the toxic buildup of an amino acid?

1. Galactosemia

2. Cystic fibrosis

3. Phenylketonuria

4. Lactose intolerance

The correct answer is: Phenylketonuria

The condition allowing for limited breastfeeding due to the toxic buildup of an amino acid is phenylketonuria (PKU). PKU is a metabolic disorder caused by a deficiency in the enzyme phenylalanine hydroxylase, which is necessary for the body to convert phenylalanine, an amino acid found in many protein-containing foods, into tyrosine. When phenylalanine accumulates in the body, especially in infants, it can lead to serious health issues, including intellectual disability and other neurological problems. Infants with PKU must adhere to a carefully managed diet that restricts phenylalanine intake. Since breast milk contains phenylalanine, breastfeeding is often limited or supplemented with specialized formulas that are low in this amino acid. This careful management helps prevent the toxic buildup of phenylalanine and supports the overall health and development of the child. The other conditions listed do not present the same issue with amino acid toxicity leading to breastfeeding limitations. For example, galactosemia is a metabolic condition involving an inability to metabolize galactose, which would lead to a different set of dietary restrictions. Cystic fibrosis primarily affects the lungs and digestive system, requiring different management strategies, and lactose intolerance pertains to the