Familial koilonychia

A 2-year-old boy with flat and spoon-shaped nail plates was referred to us. His mother had noticed that his fingernails were quite soft when he was bo rn. After 2 months, the nails became flat or spoon-shaped; the toenail plat es also became rough and flat. Systemic examination revealed nothing unusua l. All his fingernail plates were quite thin, and had concave surfaces; the distal edges of some nail plates were rough and darkened (Fig. 1). His gre at, second and middle toenails on both sides showed the same abnormalities as the fingernails. Routine laboratory tests were normal; serum levels of i ron, zinc, calcium, and magnesium were within normal limits. Repeated micro scopic examination and culture of fungi from both fingernails and toenails were negative. Histologic examination of the distal edges of some of his fi ngernail plates was basically normal. When checking members of the family, we noticed that the boy's mother and m aternal grandmother had similar nail problems (out of 14 members of three g enerations), although no systemic or other skin disorders were noticed. All the fingernails of the boy's mother were lusterless and concave with darke ning of the distal edges (Fig. 2). All her toenails were rough, lusterless, and brown; some of them had longitudinal ridges. His maternal grandmother had light brown colored fingernail plates with concave profiles (Fig. 3), a nd dark brown or even blackish colored toenails. Both the mother and matern al grandmother acknowledged that their nails were abnormal from early child hood. Repeated microscopic examination and culture of fungi from both finge rnails and toenails were negative. Several distal portions of the nail plat es were collected for histologic examination. The fingernail plates of the boy's mother showed numerous parakeratotic cells in the middle zone, and th ose of his maternal grandmother showed diffuse parakeratotic cells; melanin granules were not found in those nail plates that were checked. Taken toge ther, a diagnosis of familial koilonychia was established.