In Peibaldism ?

Ans. is 'a' i.e., Inheritance pattern is autosomal dominantPiebaldism Hypopigmentation disorderCaused by absence of melanocytes in the affected area.Autosomal dominant inheritance.There is a defect in the KIT proto - oncogene that codes for the KIT receptor. Thus defect in melanocyte survival results in hypopigmentation.KIT receptor activation by KIT ligand/ Stem Cell Factor (SCF) results in phosphorylation and potentiation of MITE Potentiation of MITF activity is responsible for melanocyte survival during development.Clinical features Depigmented patches present on the ventral or lateral trunk and in mid extremities with sparing of hands and feet.Poliosis and white forelock may be associated. Deafness is not a feature.Piebaldism with deafness is referred to as Woolf syndrome.