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. 2020 Jan 26;5(1):97–106. doi: 10.1002/epi4.12377

Table 1.

Clinical and genetic findings in HME patients

Clinical characteristics Patients
HME‐4143 HME‐4146 HME‐ 4149 HME‐6584 HME‐6593
Gender M F M M M
Year of birth 2007 2012 2002 2002 2012
Epilepsy onset 3 m 9 m 3 m 8 m 3 m
Frequency of seizures (per month)/Pre‐Op 3 80 120 150 3
Neuropsychomotor development delay Yes Yes Yes Yes Yes
Hemiparesis Not Not Yes Yes Yes
Type of seizures Focal to bilateral tonic‐ clonic Focal Generalized Focal to bilateral tonic‐ clonic Focal
Age at surgery (years) 5 2 6 13 4
EGG/ Pre‐op Asymmetric disorganization of the accentuated base activity in the left hemisphere; epileptiform paroxysms of varying morphology of continuous incidence in the frontal and temporal cerebral regions of the left hemisphere. Alternation theta in the region tempororolandica left; multifocal focal epileptiform paroxysms, polypone, acute wave and slow wave in frontotemporal‐ rolandic regions of the left cerebral hemisphere. Asymmetry of the base activity, accentuated to the right; multifocal epileptiform paroxysms of acute tip‐wave type affecting poserior quadrant and right frontal region. Increase in the frequency of discharges in the left cerebral hemisphere, with a theta and wider activity in the left parietal region and repetitive spikes in the frontal and left fronto‐polar regions. Disorganized and asymmetric base activity; continuous epileptiform paroxysms in the left cerebral hemisphere, associated with slow activity.
Type of surgery Left hemispherotomy Left hemispherotomy Right hemispherotomy Left hemispherotomy Left frontal lobectomy
Diagnosis and Histopathology PMG, GA, NH, BC I CG, CN, BC, GA, NH I CD, BC, CN, DN I DN, BC, CD, PMG I DN, CD, BC, CG I
Engel 6 months I I I I I
Engel 1 year I I I I I
Pre‐op MRI Axial and coronal MRI of FLAIR showing left and right cerebral cerebellar volume increase, with lateral ventricular dilatation and periventricular hypersignal. Axial T2‐weighted and coronal sections in FLAIR of MRI showing evidence of signal change and morphology of spins throughout the left hemisphere. Axial and coronal section of MRI in FLAIR showing right brain hemisphere enlargement, cortical thickening, lateral ventricular dilatation, and periventricular hypersignal Axial and coronal MRI of FLAIR showing increased right brain hemisphere volume, lateral ventricular dilatation. Axial and coronal section of MRI in FLAIR showing increased left cerebral hemisphere volume, cortical thickening, lateral ventricular dilatation, and periventricular hypersignal area.
Genetic screening method WES/amplicon WES/amplicon WES/amplicon Amplicon Amplicon
Gene PIK3CA, DEPDC5 MTOR PIK3CA MTOR PIK3CA
Types of variants found Missense, stop codon Missense Missense Missense Missense
HGVS

  1. p.Cys420Arg

  2. p.Arg286Ter

 p.Leu7105Phe p.Glu542Lys p.E642K p.His1047Arg
ddPCR percentage of mutated cells

  1. 22%

  2. 5%

 6% 11% 9.7% 13.1%
In silico predictions

  1. Benign (PolyPhen) Pathogenic (MutationTaster) Benign (Sift)

  2. Pathogenic (PolyPhen) Pathogenic (MutationTaster) Pathogenic (Sift)

 Pathogenic (PolyPhen) Pathogenic (MutationTaster) Pathogenic (Sift) Pathogenic (PolyPhen) Pathogenic (MutationTaster) Benign (Sift) Pathogenic (PolyPhen) Pathogenic (MutationTaster) Pathogenic (Sift) Pathogenic (PolyPhen) Pathogenic (MutationTaster) Benign (Sift)

Abbreviations: BC, balloon cells; CD, cortical demyelination; CN, cytomegalic neurons; DN, dysmorphic neurons; GA, astrogliosis; NH, heterotopia; PMG, polymicrogyria.