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. 2005 Feb 22;102(8):2975-9.
doi: 10.1073/pnas.0409852102. Epub 2005 Jan 31.

Syndromic patent ductus arteriosus: evidence for haploinsufficient TFAP2B mutations and identification of a linked sleep disorder

Arya Mani  1 , Jayaram Radhakrishnan, Anita Farhi, Khary S Carew, Carole A Warnes, Carol Nelson-Williams, Ronald W Day, Barbara Pober, Matthew W State, Richard P Lifton
Affiliations

Syndromic patent ductus arteriosus: evidence for haploinsufficient TFAP2B mutations and identification of a linked sleep disorder

Arya Mani et al. Proc Natl Acad Sci U S A. .

Abstract

Patent ductus arteriosus (PDA) is a common congenital heart disease that results when the ductus arteriosus, a muscular artery, fails to remodel and close after birth. A syndromic form of this disorder, Char syndrome, is caused by mutation in TFAP2B, the gene encoding a neural crest-derived transcription factor. Established features of the syndrome are PDA, facial dysmorphology, and fifth-finger clinodactyly. Disease-causing mutations are missense and are proposed to be dominant negative. Because only a small number of families have been reported, there is limited information on the spectrum of mutations and resulting phenotypes. We report the characterization of two kindreds (K144 and K145) with Char syndrome containing 22 and 5 affected members, respectively. Genotyping revealed linkage to TFAP2B in both families. Sequencing of TFAP2B demonstrated mutations in both kindreds that were not found among control chromosomes. Both mutations altered highly conserved bases in introns required for normal splicing as demonstrated by biochemical studies in mammalian cells. The abnormal splicing results in mRNAs containing frameshift mutations that are expected to be degraded by nonsense-mediated mRNA decay, resulting in haploinsufficiency; even if produced, the protein in K144 would lack DNA binding and dimerization motifs and would likely result in haploinsufficiency. Examination of these two kindreds for phenotypes that segregate with TFAP2B mutations identified several phenotypes not previously linked to Char syndrome. These include parasomnia and dental and occipital-bone abnormalities. The striking sleep disorder in these kindreds implicates TFAP2B-dependent functions in the normal regulation of sleep.

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Figures

Fig. 1.
Fig. 1.
Structure of TFAP2B. The genomic structure of TFAP2B is depicted, with exons as boxes; the size of introns is indicated above the diagram, and the location and consequence of mutations found in Char kindreds are indicated. “SPL” denotes splice site mutations found in K144 and K145.
Fig. 2.
Fig. 2.
Splice site mutation in TFAP2B in K144. (a) Linkage of Char syndrome to TFAP2B. The structure of K144 is shown. Solid symbols indicate members of the kindred with PDA, shaded symbols denote members of the kindred without PDA but with typical facial and hand features of Char syndrome, and open symbols denote unaffected members. (Clinical details are provided in Table 1.) The symbol with a dot in the center indicates a subject with PDA at premature birth who was considered phenotype unknown for linkage analysis. Genotypes for 11 microsatellite markers spanning the TFAP2B locus are shown. Chromosome segments that cosegregate with Char syndrome are enclosed by boxes. (b) Single-strand conformational polymorphism analysis. The results of single-strand conformational polymorphism analysis of exon 3 and its flanking exon–intron boundaries are shown in affected (denoted by asterisk) and unaffected family members. A previously uncharacterized variant found in affected members is indicated by the arrow. (c) DNA sequence of splice junction of exon 3 and intron 3. DNA sequences of an affected member of K144 (Left) and a wild-type subject (Right) are shown. A heterozygous substitution (G to A) at position +5 of the splice donor site of intron 3 is indicated by an asterisk.
Fig. 3.
Fig. 3.
Splice site mutation in K145. (a) The structure of K145 and genotypes across the TFAP2B locus are shown as in Fig. 2. Affected members all share the same haplotype, as does one unaffected member. (b) Single-strand conformational polymorphism analysis of the segment containing the intron 4–exon 5 splice junction identifies a variant in affected kindred members. (c) DNA sequence analysis of amplified segment in b identifies a heterozygous (G-to-C) splice acceptor mutation at the last base of intron 4.
Fig. 4.
Fig. 4.
Aberrant splicing of exon 3 due to TFAP2B mutation. (a) Inserts containing wild-type or mutant exon 3 and 150 bp of the flanking introns were inserted in the cloning site of the vector SPL3. The insert in each case is flanked by β-globin exons and their splice junctions. (b) Total cellular RNA was extracted from COS7 cells and reverse-transcribed, and the product was used to direct PCR using primers from the two β-globin exons as described in Methods. The products were fractionated on 1.2% agarose gel, and the results are shown for wild-type and mutant TFAP2B constructs. The wild-type construct consistently produces a 384-bp product that contains all three exons properly spliced. The mutant construct produces, either instead of or in addition to this fragment, a product of 263 bp that contains only the two β-globin exons.
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References

    1. Mitchell, S. C., Korones, S. B. & Berendes, H. W. (1971) Circulation 43, 323-332. - PubMed
    1. Hoffman, J. I. & Christianson, R. (1978) Am. J. Cardiol. 42, 641-647. - PubMed
    1. Ferencz, C., Rubin, J. D., McCarter, R. J., Brenner, J. I., Neill, C. A., Perry, L. W., Hepner, S. I. & Downing, J. W. (1985) Am. J. Epidemiol. 121, 31-36. - PubMed
    1. Gittenberger-de Groot, A. C. & Strengers, J. L. (1988) Int. J. Cardiol. 19, 153-166. - PubMed
    1. Gittenberger-de Groot, A. C., Strengers, J. L., Mentink, M., Poelmann, R. E. & Patterson, D. F. (1985) J. Am. Coll. Cardiol. 6, 394-404. - PubMed