[Post-thymus transplant vitiligo in a child with Foxn1 deficiency].

BACKGROUND: Foxn1 transcription factor deficit leads to immune deficiency, with hair and nail abnormalities. We report the case of a patient also presenting localized leucoderma.

CASE REPORT: A 3-year-old boy underwent thymus transplantation at the age of 9 months for Foxn1 deficiency. He had developed urticaria and autoimmune hypothyroidism after thymus grafting. On examination, he had universal non-scarring alopecia, nail changes (atrophy, partial onycholysis and longitudinal grooves) and leucoderma on both big toes.

DISCUSSION: This is the first description of leucoderma occurring in a patient with Foxn1 deficiency, as well as the first report of this pigment abnormality following thymus transplantation. The pathogenic hypotheses discussed were post-graft vitiligo and leucoderma induced by Foxn1 deficiency.