Biallelic variants in the calpain regulatory subunit CAPNS1 cause pulmonary arterial hypertension

Postma, Alex V.; Rapp, Christina K.; Knoflach, Katrin; Volk, Alexander E.; Lemke, Johannes R.; Ackermann, Maximilian; Regamey, Nicolas; Latzin, Philipp; Celant, Lucas; Jansen, Samara M.A.; Bogaard, Harm J.; Ilgun, Aho; Alders, Mariëlle; Spaendonck-Zwarts, Karin Y. van; Jonigk, Danny; Klein, Christoph; Gräf, Stefan; Kubisch, Christian; Houweling, Arjan C.; Griese, Matthias (2023): Biallelic variants in the calpain regulatory subunit CAPNS1 cause pulmonary arterial hypertension. Genetics in Medicine Open, 1 (1): 100811. ISSN 2949-7744

Abstract

Purpose
The aim of this study was to identify the monogenic cause of pulmonary arterial hypertension (PAH), a multifactorial and often fatal disease, in 2 unrelated consanguine families.

Methods
We performed exome sequencing and validated variant pathogenicity by whole-blood RNA and protein expression analysis in both families. Further RNA sequencing of preserved lung tissue was performed to investigate the consequences on selected genes that are involved in angiogenesis, proliferation, and apoptosis.

Results
We identified 2 rare biallelic variants in CAPNS1, encoding the regulatory subunit of calpain. The variants cosegregated with PAH in the families. Both variants lead to loss of function (LoF), which is demonstrated by aberrant splicing resulting in the complete absence of the CAPNS1 protein in affected patients. No other LoF CAPNS1 variant was identified in the genome data of more than 1000 patients with unresolved PAH.

Conclusion
The calpain holoenzyme was previously linked to pulmonary vascular development and progression of PAH in patients. We demonstrated that biallelic LoF variants in CAPNS1 can cause idiopathic PAH by the complete absence of CAPNS1 protein. Screening of this gene in patients who are affected by PAH, especially with suspected autosomal recessive inheritance, should be considered.

• Doc-Type: Article (LMU Hospital)
• Organisational unit (Faculties): 07 Medicine > Medical Center of the University of Munich > Pediatric Clinic and Outpatient Clinic in the Dr. von Hauner Children‘s Hospital
• DFG subject classification of scientific disciplines: Life sciences
• DFG: Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - 491502892