A novel mutation in GJC2 associated with hypomyelinating leukodystrophy type 2 disorder

Area of Science:

• Neurogenetics
• Molecular Medicine
• Cell Biology

Background:

• Hypomyelinating leukodystrophy type 2 (HLD2) is a genetic central nervous system disorder.
• It is caused by recessive mutations in the GJC2 gene, encoding connexin 47 (Cx47).
• HLD2 presents with neurological impairments including nystagmus, developmental delay, and ataxia.

Purpose of the Study:

• To identify the genetic cause of HLD2 in a patient.
• To characterize a novel mutation in the GJC2 gene.
• To understand the functional impact of the mutation on Cx47 and oligodendrocyte function.

Main Methods:

• Whole exome sequencing to identify mutations.
• Sanger sequencing to confirm inheritance patterns in affected and unaffected family members.
• In silico tools (PolyPhen2, SIFT, PROVEAN, CADD) for mutation functional prediction.

Main Results:

• A novel missense mutation, c.760G>A (p.Val254Met), was identified in the GJC2 gene.
• The mutation was found to be homozygous in affected individuals and heterozygous in unaffected parents, confirming autosomal recessive inheritance.
• Functional prediction scores indicated the mutation likely impairs Cx47 function.

Conclusions:

• The novel p.Val254Met mutation in GJC2 disrupts Cx47 function.
• This disruption leads to oligodendrocyte dysfunction and the hypomyelination characteristic of HLD2.
• The findings expand the understanding of GJC2 mutations in leukodystrophies.