Sorry, I should have mentioned this earlier, but this condition is also associated with mental retardation, facial asymmetry, short stature, scoliosis, and short fingers with clinodactyly.
Answer : Pigmentary Mosaicism Read more about Pigmentary Mosaicism at : Pigmentary mosaicism of the hyperpigmented type in two half-brothers - Horn - 2002 - American Journal of Medical Genetics - Wiley Online Library