Final answer:
The described symptoms suggest the infant has Phenylketonuria (PKU), a metabolic disorder caused by the inability to properly break down phenylalanine due to a deficiency in the enzyme phenylalanine hydroxylase.
Step-by-step explanation:
An infant with microcephaly, decreased skin and hair pigmentation, eczema, developmental delay, and a musty odor most likely has Phenylketonuria (PKU). PKU is a metabolic disorder where individuals lack sufficient activity of the enzyme phenylalanine hydroxylase, leading to an inability to adequately break down the amino acid phenylalanine into tyrosine. This results in high levels of phenylalanine in the body, which can cause various health issues including intellectual disability, seizures, and a distinctive musty body odor. PKU is inherited in an autosomal recessive pattern and is screened for in newborns in the United States and Canada.