The occurrence of multiple cases of incontinentia pigmenti achromians within a single family is reported for the first time. The disease is a genetic defect exhibiting autosomal dominant inheritance, and is thus a distinct entity, not a less severe variant of the Bloch-Sulzberger type of incontinentia pigmenti. The phenotype is manifest as two distinct clones of melanocytes with different structural and possibly functional properties. The appearance of the phenotypes, before the migration of melanocytes from the neural crest has occurred, may explain the bizarre pigmentary pattern.
Rubin MB. Incontinentia Pigmenti AchromiansMultiple Cases Within a Family. Arch Dermatol. 1972;105(3):424-425. doi:10.1001/archderm.1972.01620060062012