Marfan syndrome caused by a mutation in FBN1 that gives rise to cryptic splicing and a 33 nucleotide insertion in the coding sequence.
We have studied a patient with Marfan syndrome whose mutation was not detected by heteroduplex analysis. Primary cultured patient fibroblasts were metabolically labelled and found to secrete fibrillin-1 defectively when compared with an age-matched control. Sequencing of patient cDNA, isolated by reverse transcription-polymerase chain reaction of patient fibroblast RNA, detected a 33-bp insertion. The reading frame of the mutant allele was maintained and predicted the insertion of 11 amino acids at the beginning of calcium-binding epidermal growth factor-like domain 29. Direct sequencing of genomic DNA detected a heterozygous G+1-->A transversion in intron 46 of FBN1. The 11 amino acid insertion was the consequence of the usage of a cryptic splice site 33-bp downstream of the mutation. This is the first reported case of a splicing defect in FBN1 leading to the production of a full-length fibrillin-1 transcript containing a large amino acid insertion.
Hutchinson
S
S
Department of Biochemistry, University of Oxford, OX1 3QU, UK.
Wordsworth
B P
BP
Handford
P A
PA
D000328:Adult; D017398:Alternative Splicing / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics*; D000071838:Fibrillin-1; D000071837:Fibrillins; D005347:Fibroblasts; D020180:Heteroduplex Analysis; D006801:Humans; D008297:Male; D008382:Marfan Syndrome / Q000235:genetics*; D008840:Microfilament Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D054392:Adipokines
D003545:Cysteine; D000071838:Fibrillin-1; D000071837:Fibrillins; D008840:Microfilament Proteins; D012333:RNA, Messenger; C000605722:FBN1 protein, human; D054392:Adipokines