Objective: Developmental nail abnormalities are extremely heterogeneous, with hereditary isolated conditions being a small and rare subgroup. An unusual congenital nail dysplasia observed in a large South German kindred was characterized clinically to review the question of uniqueness.
Design: Case series of affected family members.
Setting: University department of dermatology and houses of patients.
Patients: The history and clinical features in 22 affected family members (13 females and 9 males, aged 5 to 74 years) were recorded and documented by photographs. Nail biopsy samples were taken from 2 patients.
Interventions: None.
Results: The pedigree spanning 5 consecutive generations was best compatible with autosomal dominant inheritance with complete penetrance. Nail alterations were mostly present since birth and soon reached an individually variable degree of severity. Affected persons showed longitudinal streaks and thinning of nail plates, mostly of all fingernails and toenails, with some accentuation of the thumbnail and big toenails, poorly developed lunulae, longitudinal angular ridges of individual nail plates occasionally starting proximally from a reddish prominence, platonychia and koilonychia of individual nails often overgrowing the lateral folds, and notches and fissures of the free margins. Histological abnormalities included a prominent granular layer of the nail matrix and epithelial strands and buds extending from the nail bed. There were no associated anomalies. Other nail dystrophies were excluded by differences in clinical and histological features.
Conclusion: The nail abnormality observed in our family represents a new autosomal dominant disorder for which we propose the term isolated congenital nail dysplasia. Arch Dermatol. 2000;136:1239-1243