NCT05127967

Consequences of Mutations in the SPG7 Gene at the Heterozygous State

Phenotypic, Biological and Functional Consequences of Mutations in the SPG7 Gene at the Heterozygous State

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 11 (actual)
• Sponsor: University Hospital, Montpellier · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Paraplegin, encoded by the SPG7 gene, is an ATP-dependent mAAA protease located in the inner mitochondrial membrane. Its function is not fully understood. Mutations in the SPG7 gene are responsible for spastic paraplegia type 7. Although spastic paraplegia type 7 is considered to be a recessive disease, some clinical observations also point to a detrimental effect of a variant in SPG7 in the heterozygous state. Thus, the presence of a single mutated variant of the SPG7 gene could be a risk factor for the development of neurological diseases. This has important implications for genetic counseling of patients and for the understanding of the function of the SPG7 protein and the mechanisms of disease development.

Detailed description

Although spastic paraplegia type 7 is considered to be a recessive disease, some clinical observations also argue for a detrimental effect of a variant in SPG7 in the heterozygous state. Thus, the presence of a single mutated variant of the SPG7 gene could be a risk factor for the development of neurological diseases. This has important implications for genetic counseling of patients and for the understanding of the function of the SPG7 protein and the mechanisms of disease development. To date there have been no studies to specifically explore the pathogenic role of single heterozygous variants in the SPG7 gene. The aim of this project is to fully characterize different models expressing single heterozygous SPG7 mutations in order to detect phenotypical, biological or functional alterations. In particular, the investigators will conduct analysis on fibroblasts from symptomatic patients with mutations in the SPG7 gene (homozygous, compound heterozygous or single heterozygous), and controls. Cellular models will be particularly useful in order to study an alteration in calcium homeostasis and in the response to ER stressors. In parallel, studies will be performed using the genetic animal model of Drosophila melanogaster.

Conditions

• SPG7

Interventions

Type	Name	Description
OTHER	Skin biopsy	A skin biopsy involves taking a piece of skin to obtain cells (fibroblasts). Skin biopsy is a minimally invasive examination and a technically simple procedure performed with a 3mm diameter punch, or with a scalpel under local anesthesia (Lidocaine patch). The procedure can be done in a consultation office with strict asepsis. It lasts 15 minutes in total + the time to reach between putting on the lidocaine patch and performing the procedure. This biopsy will usually be done on the inside of the arm. In the majority of cases, it is not helpful to close the scar with stitches.

Timeline

• Start date: 2021-11-16
• Primary completion: 2022-01-26
• Completion: 2022-01-26
• First posted: 2021-11-19
• Last updated: 2023-02-17

Locations

1 site across 1 country: France