A p.478I>T KRT1 mutation in a case of annular epidermolytic ichthyosis

Abstract

Annular epidermolytic ichthyosis (AEI; Online Mendelian Inheritance in Man [OMIM]# 607602) is a rare subtype of epidermolytic ichthyosis that is characterized by polycyclic, migratory erythematous and scaly plaques. It typically results from dominant mutations in the keratin 1 or keratin 10 genes. We present the case of a 5-year-old girl who developed intermittent eruptions of pink, round, scaly, migratory plaques with palmoplantar keratoderma and was originally diagnosed with erythrokeratodermia variabilis et progressiva (EKVP). Genetic analysis revealed a c.1436T>C transition mutation in the keratin 1 gene, and histopathology showed epidermolysis and hyperkeratosis, confirming the diagnosis of AEI.

Annular epidermolytic ichthyosis: An exceptional mild subtype of epidermolytic ichthyosis without genotype and phenotype correlation

“…Although the researchers did not provide genetic testing, their patient showed palmoplantar involvement consistent with a KRT1 gene variant. Since then, only 16 additional cases due to either KRT1 3, 4, 5 or KRT10 6, 7, 8, 9 gene pathogenic variants, belonging to 7 different families, have been published in the literature (Table I).…”

“…The condition is characterized by intermittent flares of annular and polycyclic erythematous and scaly plaques over the trunk and extremities from early infancy 3 , 4 , 6 or, more rarely, from childhood or adult life 7 , 8 . Blistering and superficial erosions are commonly present at birth, with 3 , 6 or without accompanying erythema 2 , 4 , 5 , 7 , 8 . Inconstant diffuse hyperkeratosis in the flexural areas and extensor surfaces is seen 3 , 4 , 6 , 7 …”

“…Blistering and superficial erosions are commonly present at birth, with 3 , 6 or without accompanying erythema 2 , 4 , 5 , 7 , 8 . Inconstant diffuse hyperkeratosis in the flexural areas and extensor surfaces is seen 3 , 4 , 6 , 7 3, 4, 5 whereas KRT10 variants result in sparing of the palms and soles 6, 7, 8, 9.…”

“…Inconstant diffuse hyperkeratosis in the flexural areas and extensor surfaces is seen 3 , 4 , 6 , 7 3, 4, 5 whereas KRT10 variants result in sparing of the palms and soles 6, 7, 8, 9. Unlike major forms of EI, periods of almost complete clearing are possible, except for PPK in patients with KRT1 gene variants 3, 4, 5 , 7 .…”

“…KRT1 gene variants are associated with PPK,3, 4, 5 whereas KRT10 variants result in sparing of the palms and soles 6, 7, 8, 9. Unlike major forms of EI, periods of almost complete clearing are possible, except for PPK in patients with KRT1 gene variants 3, 4, 5 , 7 . Histologically, orthokeratotic hyperkeratosis, prominent acantholysis, and a thickened granular layer with coarse keratohyalin granules are common findings, whereas vacuolar degeneration appears in both in AEI and major forms of EI, in EAI it appears in upper layers of the epidermis 3, 4, 5, 6, 7, 8, 9…”