Publication Date
1-4-2024
Journal
The American Journal of Human Genetics
DOI
10.1016/j.ajhg.2023.12.004
PMID
38181735
PMCID
PMC10806447
PubMedCentral® Posted Date
1-4-2024
PubMedCentral® Full Text Version
Post-print
Published Open-Access
yes
Keywords
Adult, Animals, Humans, Alleles, Animals, Genetically Modified, Drosophila, Drosophila Proteins, Intellectual Disability, Intracellular Signaling Peptides and Proteins, Neurodevelopmental Disorders, Protein Tyrosine Phosphatases, neurodevelopmental disorder, synaptic protein, active zone protein, Mendelian phenotypes, fruit flies
Abstract
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.
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Biological Phenomena, Cell Phenomena, and Immunity Commons, Biomedical Informatics Commons, Genetics and Genomics Commons, Medical Genetics Commons, Medical Molecular Biology Commons, Medical Specialties Commons
Comments
This article has been corrected. See Am J Hum Genet. 2024 May 8;111(6):1239. and Am J Hum Genet. 2024 Mar 20;111(4):805.
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