Novel splice donor site mutation in MERTK gene associated with retinitis pigmentosa.
OBJECTIVE
Mutations in MERTK, a member of the MER/AXL/TYRO3 receptor kinase family, have been associated with disruption of the Retinal Pigment Epithelium (RPE) phagocytosis pathway and settling of autosomal recessive RP (arRP) in humans. This study reports a novel MERTK mutation (IVS16+1G>T) in a Spanish consanguineous family presenting arRP.


METHODS
21 genes were screened by high-throughput SNP multiplexing assay. Subsequent direct sequencing was performed in exons and intronic boundaries of the cosegregating gene. The effect of the mutation in mRNA splicing was confirmed by cDNA analysis.


RESULTS
Haplotypic data revealed MERTK cosegregation with RP in affected individuals. MERTK sequencing showed a G-to-T substitution at the first nucleotide of intron 16. Finally, cDNA analysis confirmed the lack of exon 16 in the mRNA splicing process.


CONCLUSIONS
IVS16+1G>T disrupts the splice donor site causing exon 16 skipping. Absence of exon 16 causes a frameshift and, subsequently, the introduction of a premature termination codon into exon 17 creating an altered mRNA transcript with a seriously affected tyrosine kinase domain.
Brea-Fernández
A J
AJ
Grupo de Medicina Xenómica, Universidade de Santiago de Compostela, Fundación Galegade Medicina Xenómica (Consellería de Sanidade), Santiago de Compostela, Spain.
Pomares
E
E
Brión
M J
MJ
Marfany
G
G
Blanco
M J
MJ
Sánchez-Salorio
M
M
González-Duarte
R
R
Carracedo
A
A
D017398:Alternative Splicing; D003241:Consanguinity; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005799:Genes, Dominant / Q000235:genetics; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D009154:Mutation; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D022821:RNA Splice Sites / Q000235:genetics*; D012326:RNA Splicing; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D012162:Retinal Degeneration / Q000235:genetics; D012174:Retinitis Pigmentosa / Q000235:genetics*; D000076202:c-Mer Tyrosine Kinase
D011518:Proto-Oncogene Proteins; D022821:RNA Splice Sites; C097072:MERTK protein, human; D020794:Receptor Protein-Tyrosine Kinases; D000076202:c-Mer Tyrosine Kinase