Common clinical, radiologic, and pathologic features in infantile neuroaxonal dystrophy (INAD) and pantothenate kinase-associated neurodegeneration (PKAN) have led to the hypothesis of an allelic relationship. With the discovery of the gene defect in PKAN, this can now be tested directly. The authors excluded linkage in one consanguineous INAD family by haplotype analysis. Moreover, sequencing in seven INAD families revealed no mutations in PANK2 or in other genes of CoA biogenesis. Thus, INAD and PKAN are genetically heterogeneous disorders.