Recessive and dominant mutations in retinoic acid receptor beta in cases with microphthalmia and diaphragmatic hernia.
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Srour M, Chitayat D, Caron V, Chassaing N, Bitoun P, Patry L, Cordier MP, Capo-Chichi JM, Francannet C, Calvas P, Ragge N, Dobrzeniecka S, Hamdan FF, Rouleau GA, Tremblay A, Michaud JL
Recessive and dominant mutations in retinoic acid receptor beta in cases with microphthalmia and diaphragmatic hernia.
Am J Hum Genet. 2013 Oct 3;93(4):765-72. doi: 10.1016/j.ajhg.2013.08.014. Epub 2013 Sep 26.
- PubMed ID
- 24075189 [ View in PubMed]
- Abstract
Anophthalmia and/or microphthalmia, pulmonary hypoplasia, diaphragmatic hernia, and cardiac defects are the main features of PDAC syndrome. Recessive mutations in STRA6, encoding a membrane receptor for the retinol-binding protein, have been identified in some cases with PDAC syndrome, although many cases have remained unexplained. Using whole-exome sequencing, we found that two PDAC-syndrome-affected siblings, but not their unaffected sibling, were compound heterozygous for nonsense (c.355C>T [p.Arg119( *)]) and frameshift (c.1201_1202insCT [p.Ile403Serfs( *)15]) mutations in retinoic acid receptor beta (RARB). Transfection studies showed that p.Arg119( *) and p.Ile403Serfs( *)15 altered RARB had no transcriptional activity in response to ligands, confirming that the mutations induced a loss of function. We then sequenced RARB in 15 subjects with anophthalmia and/or microphthalmia and at least one other feature of PDAC syndrome. Surprisingly, three unrelated subjects with microphthalmia and diaphragmatic hernia showed de novo missense mutations affecting the same codon; two of the subjects had the c.1159C>T (Arg387Cys) mutation, whereas the other one carried the c.1159C>A (p.Arg387Ser) mutation. We found that compared to the wild-type receptor, p.Arg387Ser and p.Arg387Cys altered RARB induced a 2- to 3-fold increase in transcriptional activity in response to retinoic acid ligands, suggesting a gain-of-function mechanism. Our study thus suggests that both recessive and dominant mutations in RARB cause anophthalmia and/or microphthalmia and diaphragmatic hernia, providing further evidence of the crucial role of the retinoic acid pathway during eye development and organogenesis.