A combination of genetic and biochemical analyses for the diagnosis of PI3K-AKT-mTOR pathway-associated megalencephaly

Yutaka Negishi, Fuyuki Miya, Ayako Hattori, Yoshikazu Johmura, Motoo Nakagawa, Naoki Ando, Ikumi Hori, Takao Togawa, Kohei Aoyama, Kei Ohashi, Shinobu Fukumura, Seiji Mizuno, Ayako Umemura, Yoko Kishimoto, Nobuhiko Okamoto, Mitsuhiro Kato, Tatsuhiko Tsunoda, Mami Yamasaki, Yonehiro Kanemura, Kenjiro KosakiMakoto Nakanishi, Shinji Saitoh

研究成果: Article

11 引用 (Scopus)

抜粋

Background: Constitutive activation of the PI3K-AKT-mTOR pathway (mTOR pathway) underlies megalencephaly in many patients. Yet, prevalence of the involvement of the PI3K-AKT-mTOR pathway in patients with megalencephaly remains to be elucidated, and molecular diagnosis is challenging. Here, we have successfully established a combination of genetic and biochemical methods for diagnosis of mTOR pathway-associated megalencephaly, and have attempted to delineate the clinical characteristics of the disorder. Methods: Thirteen patients with an increased head circumference and neurological symptoms participated in the study. To evaluate the activation of the mTOR pathway, we performed western blot analysis to determine the expression levels of phosphorylated S6 ribosomal protein (phospho-S6 protein) in lymphoblastoid cell lines from 12 patients. Multiplex targeted sequencing analysis for 15 genes involved in the mTOR pathway was performed on 12 patients, and whole-exome sequencing was performed on one additional patient. Clinical features and MRI findings were also investigated. Results: We identified pathogenic mutations in six (AKT3, 1 patient; PIK3R2, 2 patients; PTEN, 3 patients) of the 13 patients. Increased expression of phospho-S6 protein was demonstrated in all five mutation-positive patients in whom western blotting was performed, as well as in three mutation-negative patients. Developmental delay, dysmorphic facial features were observed in almost all patients. Syndactyly/polydactyly and capillary malformations were not observed, even in patients with AKT3 or PIK3R2 mutations. There were no common phenotypes or MRI findings among these patients. Conclusions: A combination of genetic and biochemical methods successfully identified mTOR pathway involvement in nine of 13 (approximately 70%) patients with megalencephaly, indicating a major contribution of the pathway to the pathogenesis of megalencephaly. Our combined approach could be useful to identify patients who are suitable for future clinical trials using an mTOR inhibitor.

元の言語English
記事番号4
ジャーナルBMC Medical Genetics
18
発行部数1
DOI
出版物ステータスPublished - 2017 1 13

ASJC Scopus subject areas

  • Genetics
  • Genetics(clinical)

フィンガープリント A combination of genetic and biochemical analyses for the diagnosis of PI3K-AKT-mTOR pathway-associated megalencephaly' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

  • これを引用

    Negishi, Y., Miya, F., Hattori, A., Johmura, Y., Nakagawa, M., Ando, N., Hori, I., Togawa, T., Aoyama, K., Ohashi, K., Fukumura, S., Mizuno, S., Umemura, A., Kishimoto, Y., Okamoto, N., Kato, M., Tsunoda, T., Yamasaki, M., Kanemura, Y., ... Saitoh, S. (2017). A combination of genetic and biochemical analyses for the diagnosis of PI3K-AKT-mTOR pathway-associated megalencephaly. BMC Medical Genetics, 18(1), [4]. https://doi.org/10.1186/s12881-016-0363-6