A clinical and genotype-phenotype analysis of MACF1 variants.
Publication/Presentation Date
9-3-2025
Abstract
Microtubule-actin cross-linking factor 1 (MACF1) is a large protein of the spectraplakin family, which is essential for brain development. MACF1 interacts with microtubules through the growth arrest-specific 2 (Gas2)-related (GAR) domain. Heterozygous MACF1 missense variants affecting the zinc-binding residues in this domain result in a distinctive cortical and brain stem malformation. Evidence for other MACF1-associated disorders is still limited. Here, we present a cohort of 45 individuals with heterozygous or bi-allelic MACF1 variants to explore the phenotypic spectrum and assess possible pathogenic relevance. We observe that de novo heterozygous missense variants in the EF-hand domains also result in distinctive brain malformation and provide experimental evidence that variants in the EF-hand/GAR module increase microtubule binding, suggestive of a toxic gain of function. Notably, no phenotype-genotype correlation was possible for the remaining heterozygous variants in other domains. A clinical review of eight families with bi-allelic variants reveals a possible complex neurodevelopmental syndrome of the central and peripheral nervous systems. In these individuals, bi-allelic variants mostly affect the Plakin domain. Furthermore, RNA sequencing and chromatin immunoprecipitation (ChIP) analyses of human fetal brain tissue reveal five MACF1 isoforms with region-specific expression, differing in their exon 1 transcription start sites but splicing to a common exon 2. This differential expression explains the frontal-predominant lissencephaly in an individual with a homozygous stop-gain in exon 1 (MACF1-204: c.70C>T [p.Arg24∗]), as this isoform is preferentially expressed in the frontal cortex. We conclude that MACF1-related disorders are strictly linked to domain function and the level of transcript expression, explaining the observed wide clinical heterogeneity.
ISSN
1537-6605
Published In/Presented At
Dekker, J., Schot, R., Aldinger, K. A., Everman, D. B., Washington, C., Jones, J. R., Sullivan, J. A., Spillmann, R. C., Shashi, V., Vitobello, A., Denommé-Pichon, A. S., Mosca-Boidron, A. L., Perrin, L., Auvin, S., Zaki, M. S., Gleeson, J. G., Meave, N., Wallace, C., Nambot, S., Delanne, J., … Mancini, G. M. S. (2025). A clinical and genotype-phenotype analysis of MACF1 variants. American journal of human genetics, S0002-9297(25)00320-9. Advance online publication. https://doi.org/10.1016/j.ajhg.2025.08.010
Disciplines
Medicine and Health Sciences | Pediatrics
PubMedID
40925378
Department(s)
Department of Pediatrics
Document Type
Article