Clinical and molecular abnormalities in lipoid proteinosis.

Lipoid proteinosis (hyalinosis cutis et mucosae) is a rare, autosomal recessive disease. The main clinicopathological features comprise skin and mucous membrane infiltration and scarring with deposition of hyaline material. In this report, we describe a 6-year-old boy in whom a diagnosis of lipoid proteinosis was first suspected when he presented with blisters and erosions at 4 years, a history of life-long dysphonia and a previous epileptic convulsion. The diagnosis was confirmed by histology and identification of a homozygous frameshift mutation, 501insC, in exon 6 of the gene encoding extracellular matrix protein 1, ECM1. Lipoid proteinosis may show protean clinical features and be difficult to diagnose on clinical grounds alone. This case report illustrates that lipoid proteinosis may show protean clinical features and yet remain undiagnosed for many years. Although the gold standard for definite diagnosis remains histology, molecular characterisation of the gene mutation will add to our understanding of genotype-phenotype correlation and perhaps to the development of a rationale for future therapeutics.