poikiloderma with neutropenia
Definition A genodermatosis (OMIM:604173) characterised by poikiloderma, pachyonychia and chronic neutropenia, which begins as a papular erythematous rash on the limbs during the first year of life, gradually spreading centripetally and, as the papular rash resolves, leaving hypo- and hyperpigmentation and telangiectasias. Alopecia and leukoplakia are distinctively absent. Patients have recurrent pneumonias that trigger reactive airway disease and/or chronic cough. A key extracutaneous symptom is increased susceptibility to infections, mainly affecting the respiratory system, primarily due to a chronic neutropenia and to neutrophil functional defects. Bone marrow defects account for neutropenia and may evolve into myelodysplasia associated with the risk of leukaemic transformation. Poikiloderma with neutropenia overlaps with Rothmund-Thomson syndrome.
Molecular pathology Defects of USB1, which encodes a protein of unknown function, cause poikiloderma with neutropenia.
Synonyms Poikiloderma with neutropenia—Clericuzio-type