A seven year old male child was brought to us for fever
and was diagnosed to have Plasmodium vivax malaria with anemia and
thrombocytopenia. On general examination, he had a white forelock and
depigmented patches over the knees and a unique heart shaped depigmented
patch over the abdomen. (Fig.1) There were islands of normal
skin in the depigmented areas. Family history revealed that the paternal
grandfather and three aunts of the patient had similar features suggesting
piebaldism.
Piebaldism is inherited as an autosomal dominant
condition and is also known as partial albinism. The distribution of the
depigmented patches seen in our patient is classically described in
literature. These plaques of depigmentation are a result of a permanent
localized absence of melanocytes and melanosomes or reduced numbers of
abnormally large melanocytes. It results from mutations in the KIT
proto-oncogene, which encodes the cellular transmembrane tyrosinase kinase
for mast/stem cell growth factor. This pattern of depigmentation is
probably due to defective melanocyte proliferation or migration from the
neural crest during development. It should be differentiated from vitiligo
which is progressive and Waardenberg syndrome which has heterochromic
iris, dystopia canthorum, broad nasal root and congenital deafness, in
addition to white forelock and hypopigmentation. There are occasional
reports of piebaldism associated with type 1 Neurofibromatosis and
Rubinstein Taybi syndrome.