A novel missense mutation in exon 7 of the ECM1 gene in an Iranian lipoid proteinosis patient

Extracellular matrix protein 1 gene (ECM1) mutations in nine Iranian families with lipoid proteinosis

Background & objectives:

Lipoid proteinosis (LP) is an autosomal recessive disease. Clinical characteristics of this disease are hoarse voice, scarring of the skin, brain calcifications, and eyelid papules (moniliform blepharosis). Mutations in the ECM1 gene on 1q21.2 are responsible for this disease. This study was conducted to investigate the mutation spectrum of ECM1 gene in nine Iranian families having at least one LP patient diagnosed clinically.

Methods:

The entire ECM1 gene was screened using PCR and direct sequencing in nine Iranian families with 12 suspected LP patients who were referred to the clinic, along with their parents and siblings. Thirty healthy individuals were included as controls.

Results:

In only one patient a homozygous G>A transition at nucleotide c.806 in exon 7 was detected. A G>A substitution at nucleotide 1243 in exon 8 that changes glycine (GGT) to serine (AGT) was observed in most of our patients. Furthermore, in one patient there was a change in the sequence of intron 8, the A>T transition in nucleotide 4307. In addition, in two cases (one patient and one healthy mother with affected child) there was a C (4249) deletion in intron 8.

Interpretation & conclusions:

Our results indicate that although mutation in ECM1gene is responsible for lipoid proteinosis, it is likely that this is not the only gene causing this disease and probably other genes may be involved in the pathogenesis of the LP disease.

Production and characterization of domain-specific monoclonal antibodies against human ECM1

Human extracellular matrix protein-1 (hECM1), a secreted glycoprotein, is widely expressed in different tissues and organs. ECM1 has been implicated in multiple biological functions, which are potentially mediated by the interaction of different ECM1 domains with its ligands. However, the exact biological functions of ECM1 have not been elucidated yet, and the functional study of ECM1 has been partially hampered by the lack of sensitive and specific antibodies, especially those targeting different ECM1 domains. In this study, six strains of monoclonal antibody (MAb) against hECM1 were generated using purified, prokaryotically-expressed hECM1 as an immunogen. The MAbs were shown to be highly sensitive and specific, and suitable for western blot, immunoprecipitation assays and immunohistochemistry. Furthermore, the particular ECM1 domains recognized by different MAbs were identified. Lastly, the MAbs were found to have neutralizing activities, inhibiting the proliferation, migration and metastasis of MDA-MB-231 cells. In conclusion, the domain-specific anti-ECM1 MAbs produced in this study should provide a useful tool for investigating ECM1's biological functions, and cellular pathways in which it is involved.