Clinical and Molecular Study of the Extracellular Matrix Protein 1 Gene in a Spanish Family with Lipoid Proteinosis

BACKGROUND Lipoid proteinosis (LP) is a rare autosomal recessive disorder characterized by a hoarse voice, variable scarring, and infiltration of the skin and mucosa. This disease is associated with mutations of the gene encoding extracellular matrix protein 1 (ECM1). CASE REPORT This was a clinical and molecular study of a new case of LP with a severe phenotype. A 35-year-old female born to nonconsanguineous parents developed dermatological and extracutaneous symptoms in her 9th month of life. The neurological abnormalities of the disease began to appear at the age of 19 years. Computed tomography revealed cranial calcifications. CONCLUSIONS The diagnosis of LP was confirmed by histopathological findings and direct sequencing of ECM1. A new homozygous nonsense mutation was identified in exon 7 of ECM1, c.1076G>A (p.Trp359(*)). This mutation was not detected in 106 chromosomes of healthy individuals with a similar demographic origin. Microsatellite markers around ECM1 were used to construct the haplotype in both the parents and the patient. Reports on genotype-phenotype correlations in LP point to a milder phenotype in carriers of missense mutations in the Ecm1a isoform, whereas mutations in the Ecm1b isoform are thought to be associated with more severe phenotypes. The present findings in a Spanish patient carrying a truncating mutation in exon 7 revealed complete dermatological and neurological manifestations.