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

Evaluation of cochlear involvement and hearing function in lipoid proteinosis patients

BACKGROUND

Lipoid proteinosis (LP) is a rare genodermatosis involving amorphous hyaline accumulation in the skin, oral mucosa, larynx, mucous membranes, and viscera.

AIMS

In this study, we aimed to investigate the effects of hyaline accumulation on cochlear function and hearing in LP patients.

PATIENTS/METHODS

In this prospective study, 20 patients who were followed up with a diagnosis of LP between October 2016 and April 2020 in our clinic and 20 healthy individuals of the same age and gender, as a control group, were included. Pure-tone audiometry, tympanometry, and distortion-product otoacoustic emission tests of the patient and control groups were performed. The audiological results of the LP and control groups were compared statistically.

RESULTS

In the comparison of air-conduction thresholds between groups in pure-tone audiometry, hearing thresholds in the patient group were found to be higher than the control group at frequencies of 250, 4000, 6000, and 8000 Hz for the right ear, and 500 and 4000 Hz for the left ear. In the comparison of signal-noise responses between groups in distortion-product otoacoustic emission (DP-OAE) test, signal-noise responses in the right and left ear at frequencies of 1000, 2000, 4000, and 6000 Hz were lower in the patient group than in the control group.

CONCLUSION

We found that the cochlear functions of patients with LP were affected due to the increase in hearing thresholds and decreased signal-noise responses. We think that LP patients are candidates for hearing loss in their later life.

Extracellular Matrix Protein 1 Gene Mutation in Turkish Patients with Lipoid Proteinosis

Background:

Lipoid proteinosis (LP) is a rare autosomal recessive genodermatosis characterized by mucocutaneous lesions and hoarseness of voice that develop in early childhood. LP is caused by mutation in the extracellular matrix protein 1 (ECM1) gene, which is located on 1q21.2.

Aims:

This study aimed to present the profile of ECM1 gene mutations and to identify possible novel mutations specific to Turkey.

Materials and Methods:

The ECM1 gene mutations of 19 LP patients from five families were evaluated using DNA isolated from peripheral blood samples. All ten exons in the ECM1 gene region were amplified by polymerase chain reaction (PCR). The PCR products were analyzed using a DNA sequencing analyzer. The results of DNA sequencing were analyzed with bioinformatics methods.

Results:

of the 19 LP patients evaluated in our study, we detected defects in exon 6 (c.507delT, 658T>G), exon 9 (157C>T, 727C>T), and exon 10 (c.93_94delGCinsTT) of the ECM1 gene.

Conclusions:

Our results indicate that defects in exons 6, 9, and 10 of the ECM1 gene were responsible for LP in our country. The identification of these pathogenic mutations is valuable because it facilitates early diagnosis and genetic counseling.

Pathogenetic mechanism of lipoid proteinosis caused by mutation of the extracellular matrix protein 1 gene

Lipoid proteinosis (LP) is a rare form of dermatosis with autosomal recessive inheritance. The present study hypothesized that an extracellular matrix protein 1 (ECM1) gene mutation forms the pathological basis of LP. The association between ECM1 mutation and LP; however, requires further investigation and was thus investigated in the present study. Injury skin tissue samples from patients with LP were collected, along with venous blood samples for genomic DNA extraction. Immunohistochemical staining was performed. Polymerase chain reaction (PCR) was then used to obtain an ECM1 gene fragment, which was sequenced and compared with healthy individuals. Histopathological examination revealed that all included patients fitted the features of LP and PCR amplification of the ECM1 gene in all patients obtained positive results. Patients with LP in the present study exhibited point mutations in the ECM1 gene, including one homozygous mutation (C220G) as previously reported, and one novel homozygous mutation c.508insCTG and two heterozygous mutations (C220G/P.R481X and c507delT/c.l473delT). LP is correlated with ECM1 gene mutation.

Lipoid proteinosis: A clinical and molecular study in Egyptian patients

Lipoid proteinosis (LP) is an autosomal recessive disorder caused by the loss of function of ECM1 gene. Clinical features include varying degrees of skin thickening, hoarseness of voice and less frequently neuropsychiatric abnormalities. Twelve patients from ten unrelated families with a clinical diagnosis of lipoid proteinosis were enrolled in this study. Extraction of DNA samples of the 12 patients and their parents from peripheral blood by standard methods was performed. Polymerase chain reaction (PCR) amplification of the ECM1 gene was conducted using eight pairs of primers spanning over the 10 exons and splice junctions. Patients exhibited a variety of clinical manifestations with skin affection and hoarseness of voice being the consistent feature. We identified five novel homozygous insertion, small deletion, missense, and splice site mutations as well as two homozygous previously published splice site mutation c.70+1G>C in intron 1 and c.1305-2A>G in intron 8. The specific mutations were: c.10_11insC in exon 1, c.690_691delAG in exon 6, c.734G>A in exon 7, c.1286_1287delAA in exon 8 and c.1393-1G>T in intron 9. The novel mutations c.1393-1G>T and c.10_11insC occurred in three (30%) and two (20%) unrelated patients of the studied families, respectively. Further studies may designate an increased frequency of these mutations among Egyptian LP patients. Identification of pathogenic ECM1 mutations is important for accurate diagnosis and proper genetic counseling.