Hypomelanosis of Ito-A Case of Pigmentary Mosaicism Associated with Partial Trisomy of Chromosome 20

Introduction: Hypomelanosis of Ito is characterized by hypopigmentation along the lines of Blaschko, evident at birth or during childhood, in combination with variable extra cutaneous findings, mainly affecting the central nervous system, musculoskeletal system and eyes. Most common lyis caused by chromosomal mosaicism associated with a variety of changes in structure or number of autosomes or X chromosome. Case report: Female patient,8 years old, with a history of left renal agenesis, congenital strabismus, bone malformation of the first two left ribs with fusion of their anterior arcs, kyphoscoliosis, and delayed psychomotor development with learning and language difficulties. Referenced for hypopigmented linear bilateral macules and patches along the lines of Blaschko, on the trunk and limbs, since the age of 4. No change of hair, nails, palms, soles and mucous membranes. No previous personal or family history of skin condition, namely vesiculobullous, verrucous or pigmentation lesions. The karyotype of hypopigmented skin fibroblasts revealed the existence of partial trisomy of chromosome 20 in mosaic (mos47, XX, +20 /46,XX). Discussion: We emphasized this case by the presence of neuro cutaneous pathology associated with partial trisomy of chromosome20detected oncytogenetic analyses of skin fibroblast cultures. This chromosomal mosaicism is often associated with renal and sometimes psychomotor changes, although in some publications the psychomotor development is considered normal. The prognosis is mainly determined by the associated extracutaneous manifestations so a multidisciplinary approach to these patients is imperative.