ESPE Abstracts (2016) 86 FC3.3

Contribution of GLI2 Mutations to Pituitary Deficits and Delineation of the Associated Phenotypic Spectrum

Enzo Cohena, Aurélie Phama, Florence Dastota,b, Nathalie Collotb, Alexandra Afenjarc, Jean-Claude Careld, Jean Furiolie, Juliane Legerd, Bruno Leheupf, Brigitte Mignotg, Catherine Naud-Saudreauh, Sylvie Nivoti, Michel Polakj, Raphael Rappaportj, Dominique Simond, Pierre Sizonenkok, Catherine Vincent-Delormel, Amnon Zungm, Serge Amselema,b & Marie Legendrea,b

aInserm UMR_S933 and UPMC Université Paris 06, Hôpital Trousseau, Paris, F-75012, France; bU.F. de Génétique moléculaire, Hôpital Trousseau, AP-HP, Paris, F-75012, France; cService de Neuropédiatrie, Hôpital Trousseau, AP-HP, Paris, F-75012, France; dService d’Endocrinologie pédiatrique, Hôpital Robert Debré, AP-HP, Paris, F-75019, France, eService de Pédiatrie, Centre Hospitalier de Mantes-La-Jolie, Mantes-La-Jolie, France, fService de Médecine infantile, CHU de Nancy, Vandoeuvre, France, gService de Pédiatrie 1, CHU de Besançon, Besançon, France, hService d’Endocrinologie pédiatrique, Hôpital du Scorff, CHBS, Lorient, France, iUnité fonctionnelle d’Endocrinologie pédiatrique, CHU de Rennes, Hôpital Sud, Rennes, France, jService d’Endocrinologie pédiatrique, Hôpital Necker, AP-HP, Paris, F-75015, France, kService de Pédiatrie, Hôpital de la Tour, Geneva, Switzerland, lService de Génétique médicale, CH d’Arras, Arras, France, mPediatric Endocrinology unit, Kaplan Medical Center, Rehovot, Israel

Background: GLI2 is a zinc-finger transcription factor of the SHH signaling pathway, expressed during ventral forebrain and pituitary development. GLI2 mutations account for microforms of dominant holoprosencephaly. So far, only 15 unambiguous mutations were found in hypopituitarism –essentially combined pituitary hormone deficiency (CPHD)– frequently associated with holoprosencephaly-like malformations and/or polydactyly.

Objective and hypotheses: To i) assess the prevalence of GLI2 mutations in patients with CPHD, isolated GH deficiency (IGHD) or isolated diabetes insipidus, associated with a personal or family history of midline defects and/or polydactyly/syndactyly, ii) provide a most complete description of GLI2-associated phenotypes.

Method: Sequencing of GLI2 coding exons in 206 independent probands.

Results: Twenty rare heterozygous variations (allele frequency <0.05 in ExAC) were identified in 23 probands. Nine are non-ambiguously deleterious: 3 nonsense mutations [p.(Arg264*), p.(Tyr893*) and p.(Gln1145*)], 5 frameshifts [p.(Asp129Glyfs*159), p.(Gly198Argfs*153), p.(Leu788Argfs*16), p.(His959Profs*72) and p.(*1587Tyrext*46)] and 1 missense variation in the first zinc finger (p.Tyr435Cys). Five missense variations [p.Pro63Leu, p.Arg473His, p.Ser831del, p.Ser941Arg and p.Arg1382His], located in functional domains, are probably deleterious (charge/steric change and involvement of residues invariant throughout evolution). Six other missense variations [p.Ala117Thr, p.Gly619Ser, p.Arg720His, p.Ala1077Val, p.Pro1228Leu, p.Asp1435Glu] would require functional studies. The 14 patients with a deleterious/probably deleterious mutation had IGHD (n=8) or CPHD (n=6). The extra-pituitary defects were: bilateral cleft lip/palate (n=3), unique central median incisor (n=2), choanal atresia/hypoplasia (n=3), corpus callosum anomaly (n=2), polydactyly (n=2), 2–3 foot syndactyly (n=3) and septum pellucidum agenesis (n=1). Among the seven relatives carrying a deleterious mutation, one had isolated polydactyly, and six were asymptomatic, thereby underlining the difficult aspects of genetic counseling.

Conclusion: In this large series of patients with hypopituitarism and a personal or family history of midline defects and/or digit anomalies, GLI2 mutations, which are associated with a wide range of extra-pituitary defects, are responsible for at least 7% (14/206) of independent cases.

Article tools

My recent searches

No recent searches.