A syndromic neurodevelopmental disorder caused by rare variants in PPFIA3.

PPFIA3 encodes the protein-tyrosine phosphatase, receptor-type, F-polypeptide-interacting-protein-alpha-3 (PPFIA3), which is a member of the LAR-protein-tyrosine phosphatase-interacting-protein (liprin) family involved in synapse formation and function, synaptic vesicle transport, and presynaptic active zone assembly. The protein structure and function are evolutionarily well conserved, but human diseases related to PPFIA3 dysfunction are not yet reported in OMIM. Here, we report 20 individuals with rare PPFIA3 variants (19 heterozygous and 1 compound heterozygous) presenting with developmental delay, intellectual disability, hypotonia, dysmorphisms, microcephaly or macrocephaly, autistic features, and epilepsy with reduced penetrance. Seventeen unique PPFIA3 variants were detected in 18 families. To determine the pathogenicity of PPFIA3 variants in vivo, we generated transgenic fruit flies producing either human wild-type (WT) PPFIA3 or five missense variants using GAL4-UAS targeted gene expression systems. In the fly overexpression assays, we found that the PPFIA3 variants in the region encoding the N-terminal coiled-coil domain exhibited stronger phenotypes compared to those affecting the C-terminal region. In the loss-of-function fly assay, we show that the homozygous loss of fly Liprin-α leads to embryonic lethality. This lethality is partially rescued by the expression of human PPFIA3 WT, suggesting human PPFIA3 function is partially conserved in the fly. However, two of the tested variants failed to rescue the lethality at the larval stage and one variant failed to rescue lethality at the adult stage. Altogether, the human and fruit fly data reveal that the rare PPFIA3 variants are dominant-negative loss-of-function alleles that perturb multiple developmental processes and synapse formation. Copyright © 2023 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Citation

Maimuna S Paul, Sydney L Michener, Hongling Pan, Hiuling Chan, Jessica M Pfliger, Jill A Rosenfeld, Vanesa C Lerma, Alyssa Tran, Megan A Longley, Richard A Lewis, Monika Weisz-Hubshman, Mir Reza Bekheirnia, Nasim Bekheirnia, Lauren Massingham, Michael Zech, Matias Wagner, Hartmut Engels, Kirsten Cremer, Elisabeth Mangold, Sophia Peters, Jessica Trautmann, Jessica L Mester, Maria J Guillen Sacoto, Richard Person, Pamela P McDonnell, Stacey R Cohen, Laina Lusk, Ana S A Cohen, Jean-Baptiste Le Pichon, Tomi Pastinen, Dihong Zhou, Kendra Engleman, Caroline Racine, Laurence Faivre, Sébastien Moutton, Anne-Sophie Denommé-Pichon, Hyun Yong Koh, Annapurna Poduri, Jeffrey Bolton, Cordula Knopp, Dong Sun Julia Suh, Andrea Maier, Mehran Beiraghi Toosi, Ehsan Ghayoor Karimiani, Reza Maroofian, Gerald Bradley Schaefer, Vijayalakshmi Ramakumaran, Pradeep Vasudevan, Chitra Prasad, Matthew Osmond, Sarah Schuhmann, Georgia Vasileiou, Sophie Russ-Hall, Ingrid E Scheffer, Gemma L Carvill, Heather Mefford, Undiagnosed Diseases Network, Carlos A Bacino, Brendan H Lee, Hsiao-Tuan Chao. A syndromic neurodevelopmental disorder caused by rare variants in PPFIA3. American journal of human genetics. 2024 Jan 04;111(1):96-118

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PMID: 38181735

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