The Genetic Landscape of Polymicrogyria

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Polymicrogyria (PMG) is a common complex cortical malformation characterized by numerous small gyri and shallow sulci.
• It is classified as a neuronal migration disorder, highlighting disruptions in brain development.
• The genetic basis of PMG is supported by familial cases and its association with chromosomal abnormalities and specific gene mutations.

Purpose of the Study:

• To review the genetic underpinnings of polymicrogyria.
• To discuss the role of chromosomal aberrations and gene mutations in PMG etiology.
• To propose a gene panel for detecting cortical malformations.

Main Methods:

• Literature review of genetic factors in polymicrogyria.
• Analysis of chromosomal abnormalities associated with PMG (e.g., 22q11.2 deletion, 1p36 deletion).
• Identification of specific gene mutations linked to PMG (e.g., GPR56, TUBB2B, PAX6).

Main Results:

• Chromosomal abnormalities like deletions, duplications, and aneuploidies are frequently observed in PMG.
• Mutations in genes such as GPR56, TUBB2B, and PAX6 are associated with PMG, though they account for a minority of cases.
• The diverse functions of implicated gene products suggest disruption of multiple biological pathways in PMG pathogenesis.

Conclusions:

• Polymicrogyria results from the disruption of various biological pathways due to genetic factors.
• Both Mendelian and non-Mendelian inheritance patterns are observed in PMG.
• A gene panel approach is suggested for the diagnosis of cortical development malformations like PMG.