A 2‐year‐old Saudi boy was seen in our dermatology clinic with symmetrical, brown, linear macules over the legs, trunk, and arms (Figs 1–3). He was a product of a full‐term vaginal delivery following an uneventful first pregnancy in a 22‐year‐old mother. The birth weight was 2.3 kg. The hyperpigmented macules followed the lines of Blaschko and were noticed a few months after birth; they had enlarged with body growth until the age of 18 months. There was no family history of a similar condition and the boy's parents were unrelated. No blistering or inflammatory changes preceded the hyperpigmentation. The palms, soles, nails, scalp, mucous membranes, and teeth were normal. In addition to the hyperpigmented macules, the patient started to have generalized convulsions at the age of 2 months. 1 Linear hyperpigmented macules following the lines of Blaschko 2 Close up view of the hyperpigmented macules 3 Trunk: Hyperpigmented macules in whorled distribution Physical examination revealed delayed developmental milestones, microphthalmia, depressed nose, and high arched palate with no other abnormalities. Blood tests were normal. Magnetic resonance imaging of the brain showed changes suggestive of a demyelinating process at the parieto‐occipital white matter. Echocardiography revealed an atrial septal defect. Electroretinography (ERG), visual evoked potentials (VEP), and auditory evoked potentials (AEP) were normal. Electroencephalogram (EEG) showed multifocal epileptic discharge in the posterior region. A punch skin biopsy taken from the hyperpigmented lesions showed an increase in the melanin content of the basal layer with no incontinence of pigment or melanophages in the dermis.