51. A novel dominant-negative FGFR1 variant causes Hartsfield syndrome by deregulating RAS/ERK1/2 pathway.
- Author
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Palumbo P, Petracca A, Maggi R, Biagini T, Nardella G, Sacco MC, Di Schiavi E, Carella M, Micale L, and Castori M
- Subjects
- Amino Acid Substitution, Female, Fingers pathology, Genes, Dominant, Humans, Male, Mitogen-Activated Protein Kinase 1 genetics, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3 genetics, Mitogen-Activated Protein Kinase 3 metabolism, ras Proteins genetics, ras Proteins metabolism, Cleft Lip genetics, Cleft Lip metabolism, Cleft Lip pathology, Cleft Palate genetics, Cleft Palate metabolism, Cleft Palate pathology, Fingers abnormalities, Hand Deformities, Congenital genetics, Hand Deformities, Congenital metabolism, Hand Deformities, Congenital pathology, Holoprosencephaly genetics, Holoprosencephaly metabolism, Holoprosencephaly pathology, Intellectual Disability genetics, Intellectual Disability metabolism, Intellectual Disability pathology, MAP Kinase Signaling System, Mutation, Missense, Receptor, Fibroblast Growth Factor, Type 1 genetics, Receptor, Fibroblast Growth Factor, Type 1 metabolism
- Abstract
Hartsfield syndrome (HS) is an ultrarare developmental disorder mainly featuring holoprosencephaly and ectrodactyly. It is caused by heterozygous or biallelic variants in FGFR1. Recently, a dominant-negative effect was suggested for FGFR1 variants associated with HS. Here, exome sequencing analysis in a 12-year-old boy with HS disclosed a novel de novo heterozygous variant c.1934C>T in FGFR1 predicted to cause the p.(Ala645Val) amino-acid substitution. In order to evaluate whether the variant, changing a highly conserved residue of the kinase domain, affects FGFR1 function, biochemical studies were employed. We measured the FGFR1 receptor activity in FGF2-treated cell lines exogenously expressing wild-type or Ala645Val FGFR1 by monitoring the activation status of FGF2/FGFR1 downstream pathways. Our analysis highlighted that RAS/ERK1/2 signaling was significantly perturbed in cells expressing mutated FGFR1, in comparison with control cells. We also provided preliminary evidence showing a modulation of the autophagic process in cells expressing mutated FGFR1. This study expands the FGFR1 mutational spectrum associated with HS, provides functional evidence further supporting a dominant-negative effect of this category of FGFR1 variants and offers initial insights on dysregulation of autophagy in HS.
- Published
- 2019
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