Patau syndrome (trisomy 13) was first described by Patau in 1960. It is a rare chromosomal anomaly with severe physical and developmental abnormalities. The mosaic type does not present with the same phenotypic features and children with this type live longer because of the less severe affection of the body organs. Hypomelanosis of Ito was first described by Ito in 1952. Hypomelanosis of Ito is sporadic, however some case reports highlighted the disorder as a non–specific expression of chromosomal mosaicism including mosaic trisomy 13. We present a case of mosaic trisomy 13 with hypomelanosis of Ito and hemihypertrophy as an unusual combination of signs for the diagnosis and counseling of chromosomal aberrations.