Molecular mechanisms determining severity in patients with Pierson syndrome

Shogo Minamikawa, Saori Miwa, Tetsuji Inagaki, Kei Nishiyama, Hiroshi Kaito, Takeshi Ninchoji, Tomohiko Yamamura, China Nagano, Nana Sakakibara, Shingo Ishimori, Shigeo Hara, Norishige Yoshikawa, Daishi Hirano, Ryoko Harada, Riku Hamada, Natsuki Matsunoshita, Michio Nagata, Yuko Shima, Koichi Nakanishi, Hiroaki NagaseHiroki Takeda, Naoya Morisada, Kazumoto Iijima, Kandai Nozu

Research output: Contribution to journalArticlepeer-review

Abstract

Null variants in LAMB2 cause Pierson syndrome (PS), a severe congenital nephrotic syndrome with ocular and neurological defects. Patients’ kidney specimens show complete negativity for laminin β2 expression on glomerular basement membrane (GBM). In contrast, missense variants outside the laminin N-terminal (LN) domain in LAMB2 lead to milder phenotypes. However, we experienced cases not showing these typical genotype–phenotype correlations. In this paper, we report six PS patients: four with mild phenotypes and two with severe phenotypes. We conducted molecular studies including protein expression and transcript analyses. The results revealed that three of the four cases with milder phenotypes had missense variants located outside the LN domain and one of the two severe PS cases had a homozygous missense variant located in the LN domain; these variant positions could explain their phenotypes. However, one mild case possessed a splicing site variant (c.3797 + 5G>A) that should be associated with a severe phenotype. Upon transcript analysis, this variant generated some differently sized transcripts, including completely normal transcript, which could have conferred the milder phenotype. In one severe case, we detected the single-nucleotide substitution of c.4616G>A located outside the LN domain, which should be associated with a milder phenotype. However, we detected aberrant splicing caused by the creation of a novel splice site by this single-base substitution. These are novel mechanisms leading to an atypical genotype–phenotype correlation. In addition, all four cases with milder phenotypes showed laminin β2 expression on GBM. We identified novel mechanisms leading to atypical genotype–phenotype correlation in PS.

Original languageEnglish
Pages (from-to)355-362
Number of pages8
JournalJournal of Human Genetics
Volume65
Issue number4
DOIs
Publication statusPublished - Apr 1 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Genetics
  • Genetics(clinical)

Fingerprint Dive into the research topics of 'Molecular mechanisms determining severity in patients with Pierson syndrome'. Together they form a unique fingerprint.

Cite this