Variabilità fenotipica della leuconichia totale ereditaria

Leukonychia is a nail dyschromia characterised by the whitening of the nails. True leukonychia is caused by the altered keratinisation of the nail lamina, pseudoleukonychia by alterations of the lamina once formed, and apparent leukonychia by the simultaneous presence of subungeal hyperkeratosis and onycholysis, as well as alterations of the matrix or nail bed leading to apparent macro-lunula. Acquired true leukonychia is quite common and may have numerous causes. Hereditary true leukonychia is rare and may appear in isolated forms or associated with other anomalies, representing one of the symptoms of more complex multi-malformation syndromes. We report a clinical and anamnestic study of hereditary total leukonychia on the hands of 42 subjects living in a small village in Valsesia, belonging to 3 families who are probably interrelated. A family tree was constructed using registry office records dating back to 1850 and including 93 persons. Photos were also taken of the nails of 7 patients, belonging to two family branches. Isolated hereditary total leukonychia is transmitted as a dominant autosomal monogenic trait and does not appear to have any clinical properties given that is purely a cosmetic defect. No associated pathologies were found in the families studied, contrary to what is frequently reported in the literature. The only significant association was that with koilonychia which was present in 43% of cases. Leukonychia was present to various extents (total and partial) and forms (spot-like and striated) in our patients, even in the same individual. In our opinion the different clinical aspects of the disorder are an expression of the same genetic defect.