The prenatal testing for MSUD was performed during
the mother_s subsequent pregnancy and revealed
that the fetus was heterozygous for the mutation. The
healthy male neonate was born and his genotype was
tested by restriction enzyme analysis, which confirmed
the result of the prenatal testing. In summary, a late
diagnosis of MSUD in patients without an unusual
odour could occur especially in countries without neonatal
screening programs as seen in the index patient.
Mutation detection was, however, still beneficial to
the family since prenatal testing could be performed
in subsequent pregnancies. In addition, a novel mutation
was found, expanding the mutation spectrum of
this disease.