Table 3.

Allelic Disorders

GenePhenotype
AKT3 Gain-of-function variantsHemimegalencephaly 1
Focal cortical dysplasia
Megalencephaly
Loss-of-function variants 2Microcephaly & intellectual disability 3
CCND2 Loss-of-function variants 4Microcephaly & intellectual disability 4
PIK3R2 Bilateral perisylvian polymicrogyria 5
1.

Two individuals with hemimegalencephaly with the same mosaic AKT3 pathogenic variant (p.Glu17Lys; detectable in brain tissue only) have been reported. The paralogous AKT1 pathogenic variant (the equivalent change in a related gene) is associated with Proteus syndrome [Lindhurst et al 2011].

2.

Deletions resulting in presumed loss of function

3.
4.
5.

From: MPPH Syndrome

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