Previous reports of variants associated with the MAP1B gene in patients with periventricular nodular heterotopia (PVNH) have described frontally predominant PVNH and perisylvian polymicrogyria, with clinical manifestations of seizures and cognitive impairment.1
We report a family with PVNH related to a variant in the MAP1B gene. The 8-year-old index girl was admitted to our hospital for intractable epilepsy presenting with unresponsiveness, behavioral arrest, blank staring, and oral automatisms lasting for about 30 seconds. She had age-appropriate motor skills but mild intellectual disability (ID).
Exome analysis revealed a heterozygous missense variant in MAP1B (NM_005909), c.6230G>A (p.R2077H) in the index patient, her twin sister, and their mother.
Unlike the imaging pattern previously reported, the MRI showed gray matter heterotopia along the trigones and occipitotemporal horns. Additional unique features of this case included bilateral frontal dominant pachygyria, alongside subcortical band heterotopia belonging to the Lissencephaly spectrum2 seen in both twins (Figure 1).
The images showed bilateral periventricular heterotopia (white arrows), pachygyria (white arrowheads), and subcortical band heterotopia (yellow arrows).
The seizure type, ID, and neuroimaging phenotype were identical in her twin sister at the age of 9 years. Their mother had the same variation without seizures. Their grandmother had both the epileptic phenotype and mild ID since childhood (Figure 2).
Epilepsy (vertical line), MAP1B variation (NM_005909), c.6230G>A (p.R2077H) (horizontal lines).
Author Contributions
H. Xue: drafting/revision of the manuscript for content, including medical writing for content; major role in the acquisition of data; study concept or design; analysis or interpretation of data. C. Zhang: major role in the acquisition of data; analysis or interpretation of data. L. Xiang: drafting/revision of the manuscript for content, including medical writing for content; analysis or interpretation of data. W. Yue: drafting/revision of the manuscript for content, including medical writing for content; study concept or design; analysis or interpretation of data.
Study Funding
This work was supported by the China Association Against Epilepsy Research Fund (No. CJ-2022-021).
Disclosure
The authors report no relevant disclosures. Go to Neurology.org/N for full disclosures.
Footnotes
Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
The Article Processing Charge was funded by the authors.
Submitted and externally peer reviewed. The handling editor was Resident and Fellow Deputy Editor Katherine Fu, MD.
Teaching slides links.lww.com/WNL/C988
- Received October 22, 2022.
- Accepted in final form May 4, 2023.
- Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.
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