CLINICAL STUDY Screening of LHX2 in patients presenting growth retardation with posterior pituitary and ocular abnormalities Christelle Pe ´rez 1 , Florence Dastot-Le Moal 2 , Nathalie Collot 2 , Marie Legendre 1,2 , Isabelle Abadie 3 , Anne-Marie Bertrand 4 , Serge Amselem 1,2 and Marie-Laure Sobrier 1 1 Inserm U.933, Ho ˆpital Armand-Trousseau, Universite ´ Pierre et Marie Curie-Paris 6, 75571 Paris Cedex 12, France, 2 Service de Ge ´ne ´tique et d’Embryologie Me ´dicales, Assistance Publique-Ho ˆpitaux de Paris, Ho ˆpital Armand Trousseau, 75571 Paris, France, 3 Service de Pe ´diatrie, Centre Hospitalier Intercommunal, 94000 Cre ´teil, France and 4 Service de Pe ´diatrie 1, Centre Hospitalo-Universitaire, 25000 Besanc ¸on, France (Correspondence should be addressed to M-L Sobrier; Email: marie-laure.sobrier@inserm.fr) Abstract Background: In humans, pituitary hormone deficiency may be part of a syndrome including extra- pituitary defects like ocular abnormalities. Very few genes have been linked to this particular phenotype. In the mouse, Lhx2, which encodes a member of the LIM (Lin-11, Isl-1, and Mec-3) class of homeodomain proteins, was shown to be expressed during early development in the posterior pituitary, eye, and liver, and its expression persists in adulthood in the central nervous system Lhx2 K/K mice display absence of posterior pituitary and intermediate lobes, malformation of the anterior lobe, anophthalmia, and they die from anemia. Methods: We tested the implication of the LHX2 gene in patients presenting pituitary hormone deficiency associated with ectopic or nonvisible posterior pituitary and developmental ocular defects. A cohort of 59 patients, including two familial cases, was studied. Direct sequencing of the LHX2 coding sequence and intron/exon boundaries was performed. LHX2 transcriptional activity on several pituitary promoters (AGSU, PRL, POU1F1, and TSHB) was tested in vitro. Results: Six heterozygous sequence variations were identified, among which two are novel missense changes (p.Ala203Thr and p.Val333Met). In vitro, LHX2 activates transcription of TSHB, PRL, and POU1F1 promoters in the HEK293 cell line. A synergistic action of POU1F1 and LHX2 was also shown on these promoters. The two missense variations were tested and no significant difference was observed, leading to the conclusion that they are not deleterious. Conclusions: These results suggest that if LHX2 is involved in pituitary hormone deficiency associated with posterior pituitary and ocular defects, it would be a rare cause of this disease condition. European Journal of Endocrinology 167 85–91 Introduction Three lobes of dual embryonic origin compose the pituitary gland. The anterior and intermediate lobes derive from an invagination of the oral ectoderm (Rathke’s pouch), whereas the posterior lobe is an evagination of the neuroectoderm from the infundibu- lum. Rathke’s pouch and infundibulum have a close contact during embryonic development and their differentiation depends on the sequential temporal and spatial expression of signaling molecules and transcrip- tion factors (1). Among them, three members of the LIM (Lin-11, Isl-1, and Mec-3) homeodomain protein family, LHX2, LHX3, and LHX4, participate in pituitary development (2, 3). These transcription factors are made of a homeodomain and two zinc-finger LIM domains, which are involved in protein–protein interactions and may modulate the function of the homeodomain (4). In patients with syndromic forms of combined pituitary hormone deficiency (CPHD), mutations have been identified in LHX3 and LHX4 but not in the LHX2. Other genes (HESX1, SOX2, SOX3, OTX2, and GLI2) have also been implicated in syndromic forms of CPHD (for review, see (5)). In these patients, the molecular analyses are guided by an accurate descrip- tion of the disease phenotype, which relies on endocrine data, magnetic resonance imaging (MRI) of the pituitary region, and associated extrapituitary abnormalities (6). Lhx2 mRNA has been detected in the developing ventral diencephalon in mice (from e9.5) including the infundibulum and the posterior lobe of the pituitary gland (3), and its expression in the central nervous system persists in adulthood (7). The retina also evaginates from the neuroectoderm, and, before birth, Lhx2 is expressed throughout the neural retina, while postnatally, expression becomes restricted to the inner nuclear layer of the retina (8, 9). Furthermore, recent studies on mouse models have demonstrated that, during eye development, LHX2 transactivated Six6 in synergy with PAX6 (10). Lhx2 was also shown to be European Journal of Endocrinology (2012) 167 85–91 ISSN 0804-4643 q 2012 European Society of Endocrinology DOI: 10.1530/EJE-12-0026 Online version via www.eje-online.org Downloaded from Bioscientifica.com at 05/05/2021 12:04:40PM via free access