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. 2022 Jul-Aug;25(4):616-626.
doi: 10.4103/aian.aian_97_22. Epub 2022 May 5.

The Genetic Landscape of Polymicrogyria

Jesmy James  1 , Mary Iype  2   3   4 , Mithran Omana Surendran  5 , Ayyappan Anitha  1 , Sanjeev V Thomas  2   4
Affiliations

The Genetic Landscape of Polymicrogyria

Jesmy James et al. Ann Indian Acad Neurol. 2022 Jul-Aug.

Abstract

Polymicrogyria (PMG) is a relatively common complex malformation with cortical development, characterized by an exorbitant number of abnormally tiny gyri separated by shallow sulci. It is a neuronal migration disorder. Familial cases of PMG and the manifestation of PMG in patients with chromosomal aberrations and mutations indicate their important role of genetics in this disorder. The highly stereotyped and well-conserved nature of the cortical folding pattern in humans is suggestive of the genetic regulation of the process. The chromosomal abnormalities observed in PMG include deletions, duplications, chromosomal rearrangements, and aneuploidies. Two of the most common deletions in PMG are 22q11.2 deletion and 1p36 deletion. Further, mutations in several genes such as GPR56, TUBB2B, SRPX2, PAX6, EOMES, WDR62, TUBA8, KIAA1279, and COL18A1 are known to be associated with PMG. Intriguingly, these genes are responsible only for a small number of cases of PMG. The protein products of these genes are implicated in diverse molecular and cellular functions. Taken together, PMG could be the result of the disruption of several biological pathways. Different modes of Mendelian inheritance and non-Mendelian inheritance are seen in PMG. We have suggested a gene panel that can be used for the detection of malformations of cortical development.

Keywords: 22q11.2 deletion; GPR56; cortical folding; polymicrogyria; tubulins.

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Conflict of interest statement

There are no conflicts of interest.

Figures

Figure 1
Figure 1
MRI images of various patterns of polymicrogyria. Source: http://www.genereviews.org/. Copyright © 1993-2022 University of Washington
Figure 2
Figure 2
A flow chart for genetic testing and counseling of families with brain malformations
See this image and copyright information in PMC

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