Autosomal-recessive Charcot-Marie-Tooth diseases

Area of Science:

• Genetics
• Neurology
• Pathology

Background:

• Consanguineous marriages in the Mediterranean basin, particularly Algeria, contribute to a high prevalence of autosomal-recessive (AR) inheritance.
• AR inheritance accounts for over 50% of Charcot-Marie-Tooth (CMT) disease cases in these regions.
• CMT is classified into demyelinating (CMT 4/AR-CMT 1) and axonal (AR-CMT 2) forms, similar to dominant types.

Purpose of the Study:

• To analyze microscopic lesions in nerve biopsies from Algerian families with AR CMT.
• To correlate specific histologic phenotypes with underlying genetic mutations.
• To guide the search for novel CMT genotypes in consanguineous populations.

Main Methods:

• Examination of nerve biopsies from patients in consanguineous Algerian families.
• Clinical and histologic phenotype analysis.
• Genetic analysis of families with recessive transmission.

Main Results:

• Identification of novel CMT genotypes, including GDAP1, MTMR2, MTMR13, KIAA1985, NDGR1, periaxin, and lamin.
• Correlation between specific microscopic lesions and implicated genes.
• Characteristic lesions identified for CMT 4 (e.g., MTMR2, MTMR13, KIAA1985, periaxin) and AR-CMT 2 (e.g., lamin).

Conclusions:

• Nerve biopsy histology is crucial for identifying the genetic basis of AR CMT.
• Specific lesions can direct genetic testing towards particular genes like MTMR2, MTMR13, KIAA1985, periaxin, and lamin.
• Further genetic discoveries are anticipated in AR CMT, highlighting the complexity of the disease.