Incomplete penetrance for isolated congenital asplenia in humans with mutations in translated and untranslated RPSA exons.
Bolze A, Boisson B, Bosch B, Antipenko A, Bouaziz M, Sackstein P, Chaker-Margot M, Barlogis V, Briggs T, Colino E, Elmore AC, Fischer A, Genel F, Hewlett A, Jedidi M, Kelecic J, Krüger R, Ku CL, Kumararatne D, Lefevre-Utile A, Loughlin S, Mahlaoui N, Markus S, Garcia JM, Nizon M, Oleastro M, Pac M, Picard C, Pollard AJ, Rodriguez-Gallego C, Thomas C, Von Bernuth H, Worth A, Meyts I, Risolino M, Selleri L, Puel A, Klinge S, Abel L, Casanova JL.
Proc. Natl. Acad. Sci. U.S.A.
2018 Oct 2
Isolated congenital asplenia (ICA) is the only known human developmental defect exclusively affecting a lymphoid organ. In 2013, we showed that private deleterious mutations in the protein-coding region of RPSA, encoding ribosomal protein SA, caused ICA by haploinsufficiency with complete penetrance. We reported seven heterozygous protein-coding mutations in 8 of the 23 kindreds studied, including 6 of the 8 multiplex kindreds. We have since enrolled 33 new kindreds, 5 of which are multiplex. We describe here 11 new heterozygous ICA-causing RPSA protein-coding mutations, and the first two mutations in the 5'-UTR of this gene, which disrupt mRNA splicing. Overall, 40 of the 73 ICA patients (55%) and 23 of the 56 kindreds (41%) carry mutations located in translated or untranslated exons of RPSA. Eleven of the 43 kindreds affected by sporadic disease (26%) carry RPSA mutations, whereas 12 of the 13 multiplex kindreds (92%) carry RPSA mutations. We also report that 6 of 18 (33%) protein-coding mutations and the two (100%) 5'-UTR mutations display incomplete penetrance. Three mutations were identified in two independent kindreds, due to a hotspot or a founder effect. Finally, RPSA ICA-causing mutations were demonstrated to be de novo in 7 of the 23 probands. Mutations in RPSA exons can affect the translated or untranslated regions and can underlie ICA with complete or incomplete penetrance.