An uncommon coexistence of circumscribed hyperpigmentation and hypopigmentation, in close proximity to each other, is described in a 17 year old patient with various other congenital defects, such as dysmorphic facial appearance, severe kyphoscoliosis, delayed motor development, epileptic seizures, and mental retardation. We suggest the combination of hyper-and hypopigmented cutaneous lesions is an example of allelic twin spotting. Because the skin of this patient showed three different degrees of pigmentation, the term "cutis tricolor" is proposed. (7Med Genet 1997;34:676-678 On examination at the age of 17 years his height was 145 cm (18 cm below the 3rd centile), his weight was 42.4 kg (5 kg below the 3rd centile), and head circumference 52 cm (1.5 cm below the 3rd centile). He had bushy eyebrows, deep set and backward rotated ears, broad nostrils, and prognathism (figs 1 and 2). A pronounced kyphoscoliosis resulting in chest deformity was present (fig 2). His hearing appeared to be normal and his muscle tone and joint mobility were also normal. An EEG showed polyspike-wave complexes. A ventricular septal defect had been closed surgically at the age of 9 years. On ultrasonographic examination, thoracic and abdominal organs were otherwise normal. The testes were not palpable and a CT scan failed to show them within the abdomen. However, an HCG test indicated the presence of functionally active testicular tissue.On examination of the skin, a peculiar pigmentary disturbance was noted. On the right side of his body multiple segmented areas of cafe au lait hyperpigmentation involved the mandibular area and the arm. In addition, ipsilateral, well demarcated areas of hypopigmentation were present on the neck and the shoulder, in close proximity to the hyperpigmented lesions (fig 3).