Publications about genetic testing for neurological disorders
  1. Biallelic variants in the transcription factor PAX7 are a new genetic cause of myopathy

Biallelic variants in the transcription factor PAX7 are a new genetic cause of myopathy

June 04, 2019

The majority of novel disease genes is currently being identified in less well-investigated consanguineous populations. Based on its corresponding global positioning, CENTOGENE has been able to contribute significantly to such research projects. The most recent example is the discovery of recessive mutations in the transcription factor PAX7 to underlie a new form of muscle disease. The findings were published in Genetics in Medicine, one of the leading journals in the field.

Genet Med. 2019 May 16. doi: 10.1038/s41436-019-0532-z.

Abstract

PURPOSE:

Skeletal muscle growth and regeneration rely on muscle stem cells, called satellite cells. Specific transcription factors, particularly PAX7, are key regulators of the function of these cells. Knockout of this factor in mice leads to poor postnatal survival; however, the consequences of a lack of PAX7 in humans have not been established.

METHODS:

Here, we study five individuals with myopathy of variable severity from four unrelated consanguineous couples. Exome sequencing identified pathogenic variants in the PAX7 gene. Clinical examination, laboratory tests, and muscle biopsies were performed to characterize the disease.

RESULTS:

The disease was characterized by hypotonia, ptosis, muscular atrophy, scoliosis, and mildly dysmorphic facial features. The disease spectrum ranged from mild to severe and appears to be progressive. Muscle biopsies showed the presence of atrophic fibers and fibroadipose tissue replacement, with the absence of myofiber necrosis. A lack of PAX7 expression was associated with satellite cell pool exhaustion; however, the presence of residual myoblasts together with regenerating myofibers suggest that a population of PAX7-independent myogenic cells partially contributes to muscle regeneration.

CONCLUSION:

These findings show that biallelic variants in the master transcription factor PAX7 cause a new type of myopathy that specifically affects satellite cell survival.