PROP1 Mutations Research Articles

Aged PROP1 Deficient Dwarf Mice Maintain ACTH Production

Humans with PROP1 mutations have multiple pituitary hormone deficiencies (MPHD) that typically advance from growth insufficiency diagnosed in infancy to include more severe growth hormone (GH) deficiency and progressive reduction in other anterior pituitary hormones, eventually including adrenocorticotropic hormone (ACTH) deficiency and hypocortisolism. Congenital deficiencies of GH, prolactin, and thyroid stimulating hormone have been reported in the Prop1null (Prop1-/-) and the Ames dwarf (Prop1df/df) mouse models, but corticotroph and pituitary adrenal axis function have not been thoroughly investigated. Here we report that the C57BL6 background sensitizes mutants to a wasting phenotype that causes approximately one third to die precipitously between weaning and adulthood, while remaining homozygotes live with no signs of illness. The wasting phenotype is associated with severe hypoglycemia. Circulating ACTH and corticosterone levels are elevated in juvenile and aged Prop1 mutants, indicating activation of the pituitary-adrenal axis. Despite this, young adult Prop1 deficient mice are capable of responding to restraint stress with further elevation of ACTH and corticosterone. Low blood glucose, an expected side effect of GH deficiency, is likely responsible for the elevated corticosterone level. These studies suggest that the mouse model differs from the human patients who display progressive hormone loss and hypocortisolism.

Candidate genes for panhypopituitarism identified by gene expression profiling.

Mutations in the transcription factors PROP1 and PIT1 (POU1F1) lead to pituitary hormone deficiency and hypopituitarism in mice and humans. The dysmorphology of developing Prop1 mutant pituitaries readily distinguishes them from those of Pit1 mutants and normal mice. This and other features suggest that Prop1 controls the expression of genes besides Pit1 that are important for pituitary cell migration, survival, and differentiation. To identify genes involved in these processes we used microarray analysis of gene expression to compare pituitary RNA from newborn Prop1 and Pit1 mutants and wild-type littermates. Significant differences in gene expression were noted between each mutant and their normal littermates, as well as between Prop1 and Pit1 mutants. Otx2, a gene critical for normal eye and pituitary development in humans and mice, exhibited elevated expression specifically in Prop1 mutant pituitaries. We report the spatial and temporal regulation of Otx2 in normal mice and Prop1 mutants, and the results suggest Otx2 could influence pituitary development by affecting signaling from the ventral diencephalon and regulation of gene expression in Rathke's pouch. The discovery that Otx2 expression is affected by Prop1 deficiency provides support for our hypothesis that identifying molecular differences in mutants will contribute to understanding the molecular mechanisms that control pituitary organogenesis and lead to human pituitary disease.

Acquisition of steady-state operant behavior in long-living Ames Dwarf mice

Ames dwarf mice have a Prop-1 mutation that has been identified with increased levels of IGF-I in the central nervous system, upregulation of neuroprotective systems, and increased lifespan. To elucidate the behavioral effects of the Prop-1 mutation, 8 Ames dwarf and 7 normal mice (all of whom were 8months of age or younger) were compared on a differential-reinforcement-of-low-rate-of-responding schedule of reinforcement and a matching-to-sample task. On both tasks, nosepokes were reinforced with access to a saccharin solution. Comparisons were based on several measures of behavioral efficiency: pause durations, intertrial intervals, and numbers of responses. Ames dwarf mice were generally less efficient than normal mice. One possible cause of this outcome is that relatively young Ames dwarf mice show less cognitive development than age-matched normal mice.

Quelles causes génétiques rechercher en présence d’un déficit en hormone de croissance ?

Congenital growth hormone deficiency (GHD) is a rare cause of growth delay. It should be suspected when other causes of hypopituitarism (sellar tumor, postsurgical or radioinduced hypopituitarism, etc.) have been ruled out. GHD can be isolated (IGHD) or associated with at least one other pituitary hormone deficiency (CPHD) including thyrotroph, lactotroph, corticotroph, or gonadotroph deficiencies. CPHD is caused by mutations of genes coding for pituitary transcription factors involved in pituitary ontogenesis or in the hypothalamic-pituitary axis. Clinical presentation varies, depending on the type and severity of GHD, the age at diagnosis, the association with other pituitary hormone deficiencies, or extrapituitary malformations. Clinical, biological, and radiological work-up is very important to determine for which transcription factor the patient should be screened. There is a wide variety of phenotypes depending on the transcription factor involved: PROP1 (somatolactotroph, thyrotroph, gonadotroph, and sometimes corticotroph deficiencies; pituitary hyper- or hypoplasia), POU1F1 (somatolactotroph and thyrotroph deficiencies, pituitary hypoplasia), HESX1 (variable pituitary deficiencies, septo-optic dysplasia), and less frequently LHX3 (somatolactotroph, thyrotroph, and gonadotroph deficiencies, deafness, and limited head and neck rotation), LHX4 (variable pituitary deficiencies, ectopic neurohypophysis, cerebral abnormalities), and OTX2 (variable pituitary deficiencies, ectopic neurohypophysis, ocular abnormalities). Mutations of PROP1 remain the first identified cause of CPHD, and as a consequence the first to be sought. POU1F1 mutations should be looked for in the postpubertal population presenting with GH/TSH deficiencies and no extrapituitary malformations. Once genetic diagnosis has been concluded, a strict follow-up is necessary because patients can develop new deficiencies (for example, late-onset corticotroph deficiency in patients with PROP1 mutations). Identification of gene defects allows early treatment of pituitary deficiency and prevention of their potentially lethal consequences. If untreated, the main symptoms include short stature, cognitive alterations, or delayed puberty. An appropriate replacement of hormone deficiencies is therefore required. Depending on the type of transmission (recessive transmission for PROP1 and LHX3, dominant for LHX4, autosomal dominant or recessive for POU1F1 and HESX1), genetic counseling might be proposed. Genotyping appears highly beneficial at an individual and familial level.

Pituitary Stalk Dysgenesis-Induced Hypopituitarism in Adult Patients: Prevalence, Evolution of Hormone Dysfunction and Genetic Analysis

Objectives: To investigate the prevalence of pituitary stalk dysgenesis (PSD) in adult hypopituitary patients by describing the chronology of hormone deficiencies and their potential correlation with traumatic delivery, mutations in genes required for pituitary development and function and pituitary stalk visibility on MRI. Design: Retrospective and prospective study involving 231 hypopituitary patients, including 26 diagnosed with PSD. Clinical, biochemical and radiological studies were reviewed. Molecular analyses of HESX1, LHX4,PROP1 and POU1F1 genes were performed prospectively. Results: PSD was present in 11.2% of hypopituitary patients. PSD was diagnosed before 14 years of age in 46.2% of cases, between 14 and 18 years of age in 23%, and in adulthood in 30.8%. Perinatal complications or gene mutations were present in 26.9 and 4.3% of patients, respectively. At first assessment, 92.3% of patients had growth hormone (GH) deficiency. 26.9% presented as combined pituitary deficiencies and 7.6% as panhypopituitarism. Hormone deficiencies were progressive during follow-up in 84.6%. 96% progressed to multiple deficiencies and 46% to panhypopituitarism. No significant association was found between hormonal dysfunction and previous perinatal damage or breech delivery (p = 0.17), PROP1 mutations (p = 0.26) or pituitary stalk visibility on MRI (p = 0.52). No mutations in POU1F1, HESX1 and LHX-4 genes were detected. Conclusion: In this study, PSD prevalence in adult hypopituitary patients was 11.2%. Typical clinical presentation includes isolated or combined pituitary hormone deficiencies during the pediatric age, which usually progress to combined or complete hypopituitarism in adulthood. Phenotype is highly variable depending on hormone profile and age at onset.

CTNNB1 gene mutations, pituitary transcription factors, and MicroRNA expression involvement in the pathogenesis of adamantinomatous craniopharyngiomas.

Genes involved in formation/development of the adenohypophysis, CTNNB1 gene, and microRNAs might be implicated in the craniopharyngioma pathogenesis. The objective of this study is to perform the molecular analysis of HESX1, PROP1, POU1F1, and CTNNB1 genes and evaluate a panel of miRNA expression in craniopharyngioma. We also verified whether the presence of CTNNB1 mutation is associated with clinical findings and miRNA expression. The study included 16 patients with adamantinomatous craniopharyngioma (nine children and seven adults; eight females and eight males; 6-55 years, median 15.5 years). DNA, RNA, and cDNA were obtained from craniopharyngioma and normal pituitaries. DNA was also extracted from peripheral blood of healthy subjects. All genes were amplified by polymerase chain reaction and direct sequenced. Relative quantification of miRNA expression was calculated using the 2(-ΔΔCt) method. We found no mutations in HESX1, PROP1, and POU1F1 genes and four polymorphisms in PROP1 gene which were in Hardy-Weinberg equilibrium and had similar allelic frequencies in craniopharyngioma and controls. We found seven different mutations in CTNNB1 in eight of 16 patients. Younger patients presented more frequently CTNNB1 mutation than adults. We observed hyperexpression of miR-150 (1.7-fold); no different expression of miR-16-1, miR-21, and miR23a; and an underexpression of miR-141, let-7a, miR-16, miR-449, miR-145, miR-143, miR-23b, miR-15a, and miR-24-2 (ranging from -7.5 to -2.5-fold; p = 0.02) in craniopharyngioma. There was no association between tumor size or the recurrence and the presence of CTNNB1mutations. miR-16 and miR-141 were underexpressed in craniopharyngioma presenting CTNNB1 mutations. miR-23a and miR24-2 were hyperexpressed in patients who underwent only one surgery. Mutations or polymorphisms in pituitary transcription factors are unlikely to contribute to the adamantinomatous craniopharyngioma pathogenesis, differently of CTNNB1 mutations. Our data suggest the potential involvement of the deregulation of miRNA expression in the craniopharyngioma pathogenesis and outcome and also that the miRNA could modulate the Wnt signaling pathway in craniopharyngioma tumorigenesis.

W194XProp1 and S156insTProp1, both of which have intact DNA-binding domain, show a different DNA-binding activity to the Prop1-binding element in human Pit-1 gene

Prop1 activates POU1F1 (Pit-1) gene expression, which in turn stimulates GH, PRL, TSHbeta and GHRH receptor gene expressions. Therefore the patients with Prop1 mutation show GH, PRL, and TSH deficiency. The mutation of Prop1 is a major abnormality causing combined pituitary hormone deficiency (CPHD). However, DNA-binding and activating functions of mutant Prop1 have not been examined fully because Prop1-binding elements (PBEs) in human POU1F1 gene were not identified until 2008. The aim of this study is to test DNA-binding and transcriptional activities of two mutant Prop1s (W194XProp1 and S156insTProp1, both of them were found in the patients with CPHD) whose mutation is located in putative transactivating domain but not in DNA-binding domain. W194XProp1 showed a marked DNA-binding to PBE as well as a consensus element of paired-like transcription factors (PRDQ9). Activating function for POU1F1 reporter genes expression was lost or decreased in W194XProp1 but still preserved for PRDQ9 reporter gene. S156insTProp1 did not bind PBE but bound PRDQ9. Consistent with the result, S156insTProp1 did not stimulate POU1F1 reporter gene but stimulated PRDQ9 reporter gene. These results support the inference that W194XProp1 is unable to increase POU1F1 gene expression by the defect of transactivating domain and that S156insTProp1 is unable to increase due to the loss of DNA-binding activity. DNA-binding domain that has been assumed is not sufficient to provide full DNA-binding activity of Prop1 and transactivating domain of Prop1 is likely to affect DNA binding to PBE.

PROP1, HESX1, POU1F1, LHX3 and LHX4 Mutation and Deletion Screening and GH1 P89L and IVS3+1/+2 Mutation Screening in a Dutch Nationwide Cohort of Patients with Combined Pituitary Hormone Deficiency

Background/Aims: Mutation frequencies of genes involved in combined pituitary hormone deficiency (CPHD) vary substantially between populations. The HYPOPIT study aims to obtain an overall picture of known and new genetic defects and variations in a nationwide cohort of Dutch (mostly) sporadic CPHD patients. Methods: We screened 79 CPHD patients from 78 families (regardless of MRI and hormonal phenotype) for mutations and deletions in PROP1, HESX1, POU1F1, LHX3 and LHX4, as well as the P89L and IVS3+1/+2 mutations in GH1, recently described to cause pituitary hormone impairment in addition to GH deficiency. Results: We did not find any mutation or deletion in PROP1, HESX1, LHX3 or LHX4, nor GH1 P89L and GH1 IVS3+1/+2 mutations. Among 12 patients with a typical ‘POU1F1 phenotype’, 1 patient was formerly known to have a POU1F1 mutation. This results in a POU1F1 mutation frequency in these patients of 8.3%. Conclusion: Thorough screening for mutations and deletions in PROP1, HESX1, POU1F1, LHX3, LHX4, as well as screening for GH1 P89L or GH1 IVS3+1/+2 mutations, did not reveal any genetic defect in our cohort of CPHD patients except for one formerly known POU1F1 mutation in 1 patient. Future research should focus on alternative explanations for CPHD, like other genes or environmental factors.

Corepressors TLE1 and TLE3 Interact with HESX1 and PROP1

Pituitary hormone deficiency causes short stature in one in 4000 children born and can be caused by mutations in transcription factor genes, including HESX1, PROP1, and POU1F1. HESX1 interacts with a member of the groucho-related gene family, TLE1, through an engrailed homology domain and represses PROP1 activity. Mice with Prop1 deficiency exhibit failed differentiation of the POU1F1 lineage, resulting in lack of TSH, GH, and prolactin. In addition, these mutants exhibit profound pituitary dysmorphology and excess Hesx1 and Tle3 expression. The ability of HESX1 to interact with TLE3 has not been explored previously. We tested the ability of TLE3 to enhance HESX1-mediated repression of PROP1 in cell culture. Both TLE3 and TLE1 repress PROP1 in conjunction with HESX1 with similar efficiencies. TLE1 and TLE3 can each repress PROP1 in the absence of HESX1 via a protein-protein interaction. We tested the functional consequences of ectopic TLE3 and HESX1 expression in transgenic mice by driving constitutive expression in pituitary thyrotrophs and gonadotrophs. Terminal differentiation of these cells was suppressed by HESX1 alone and by TLE3 and HESX1 together but not by TLE3 alone. In summary, we present evidence that HESX1 is a strong repressor that can be augmented by the corepressors TLE1 and TLE3. Our in vitro studies suggest that TLE1 and TLE3 might also play roles independent of HESX1 by interacting with other transcription factors like PROP1.

Pituitary Enlargement in Patients with PROP1 Gene Inactivating Mutation Represents Cystic Hyperplasia of the Intermediate Pituitary Lobe. Histopathology and Over 10 Years Follow-up of Two Patients

Patients with a PROP1 inactivating mutation present combined pituitary hormone deficiency (CPHD) and pituitary maldevelopment. A retrospective analysis of 31 CPHD patients with a PROP1 mutation revealed two individuals, aged 18 and 4.5 years, who had undergone subtotal surgery to remove pituitary tumors, 16.8 x 12 mm and 9 x 10 x 12 mm in size. Histological reassessment of tissue samples revealed epithelial cells, partially oxyphilic, forming gland-like microcystic structures, most of them filled with eosinophilic colloid. These structures were directly linked with fragments of the posterior lobe. Neither atypia nor any traces of proliferation activity (Ki-67 LI=0%) were noted. Immunohistochemistry showed the presence of all hormonal phenotypes of cells. These findings corresponded to the intermediate lobe of the pituitary gland. For this type of pathology we propose the term 'cystic hyperplasia of the intermediate pituitary lobe' and suggest PROP1 gene assessment in patients with CPHD in order to avoid unnecessary neurosurgical interventions.

Molecular analysis of novel PROP1 mutations associated with combined pituitary hormone deficiency (CPHD)

Homozygous mutations in the gene encoding the pituitary transcription factor PROP1 are associated with combined pituitary hormone deficiency (CPHD) in both mice and humans with a highly variable phenotype with respect to the severity and time of initiation of pituitary hormone deficiency. We have ascertained three pedigrees with PROP1 mutations from a large cohort of patients with variable degrees of CPHD who were screened for mutations in PROP1. Affected individuals from all three pedigrees were found to harbour novel PROP1 mutations. We have identified two siblings in one family who were homozygous for an intronic mutation (c.343-11C > G) that disrupts correct splicing resulting in the loss of exon 3 from the PROP1 transcript. Two siblings from a second, unrelated family are compound heterozygotes for two point mutations in the coding region, a missense mutation (p.R125W) that leads to impaired transcriptional activation, and a deletion of a single nucleotide (c.310delC) resulting in a frameshift and nonfunctional mutant protein. Additionally, we identified a homozygous deletion of the PROP1 locus in two patients born to consanguineous parents. Mutations in PROP1 are a frequent cause of familial CPHD. We have described four novel mutations in PROP1 in 3 pedigrees, all resulting in PROP1 deficiency by different mechanisms. The phenotypic variation observed in association with PROP1 mutations both within and between families, together with the evolving nature of hormone deficiencies and sometimes changing pituitary morphology indicates a need for continual monitoring of these patients.

Insulin/IGF-1 and ROS signaling pathway cross-talk in aging and longevity determination.

Regulation of hormonal, insulin/IGF-1 (Ins/IGF-1) signaling activities, and pathways of the intrinsic generation of reactive oxygen species (ROS) play a role in aging and longevity determination. In this review we discuss the cross-talk between these pathways as mechanisms of signaling that may be important factors in the regulation of aging and longevity. The balance of physiological processes controlling the rate of aging and longevity in several mouse mutants suggests the involvement of cross-talk mechanisms of regulation of the insulin/IGF1 signaling pathway vs. the ROS signaling pathways. In mice, modulation of the Ins/IGF-1 signaling pathways resulting from the Prop1(df), Pit1(dw) and Igf1 receptor mutations exemplify the hormonal pathways associated with aging and longevity determination. These pathways are also targets of the ROS-mediated redox pathways. Similarly, the Klotho and p66(Shc) mutants link regulation of ROS signaling pathways to aging and longevity determination. Both of these models also display altered insulin signaling activity, a characteristic associated with longevity. The Ins/IGF-1 signaling pathway is of particular interest because of its decreased activity due to genetic manipulation vs. its responsiveness to ROS levels.

PCR-SSCP and <i>Hin6</i>I PCR-RFLP detecting novel anonymous SNPs within ovine <i>PROP1</i> gene (Brief report)

Abstract. PROP1 plays a direct or indirect key role in the ontogenesis of pituitary gonadotropes, as well as somatotropes, lactotropes and caudomedial thyrotropes (WU et al., 1998). Mutations of PROP1 are responsible for deficiencies of POU1F1, GH, prolactin (PRL) and thyroid stimulating hormone (TSH) in Snell and Jackson dwarf mice and in man, as well as deficiencies of LH and FSH, suggesting that the PROP1 gene is a potential candidate gene associating with production traits in animal breeding and genetics. To date, no polymorphism of PROP1 gene has been reported in ruminant animals except bovine (PAN et al., 2007). So, the objective of this study is to investigate the polymorphism of all coding regions within ovine PROP1 gene by PCR-SSCP, DNA sequencing and PCR-RFLP methods, which will possibly contribute to conducting association analysis and evaluating them as genetic markers in animal breeding and genetics.

Congenital hypopituitarism: report of 23 cases

Congenital hypopituitarism is an uncommon cause of hypophyseal insufficiency It is less common than growth hormone deficiency which has an incidence of 1:4.000 to 1:8.000 live newborns. Early diagnosis of this condition is important to prevent impairment of cognitive function, poor growth and alterations in metabolic profile in these patients. To report 23 patients diagnosed with congenital hypopituitarism. Retrospective review of clinical records of 23 patients (12 males) with congenital hypopituitarism, diagnosed during a 21 years period. In a group of 16 patients a molecular study was performed searching for mutations in HESX1, PROP-1 or POUF-1. Short stature was the most frequent sign at the first evaluation, followed by neonatal hypoglycemia and presence of nystagmus, strabismus, atrophic optic nerve or malformations in the middle line showed in CNS imaging, suggesting septo-optic-dysplasia. All male patients diagnosed during neonatal period, exhibited micropenis. CNS images showed isolated hypophyseal hypoplasia or associated to an ectopic neurohypophysis in most patients. No patient in the subgroup subjected to molecular analysis had any of the mutations in the searched genes. The diagnosis of hypopituitarism must be based on clinical grounds, especially when hypoglycemia, prolonged jaundice, micropenis or midline alterations are found in the neonatal period.

Hipopituitarismo congénito: Experiencia en 23 casos

Congenital hypopituitarism is an uncommon cause of hypophyseal insufficiency It is less common than growth hormone deficiency which has an incidence of 1:4.000 to 1:8.000 live newborns. Early diagnosis of this condition is important to prevent impairment of cognitive function, poor growth and alterations in metabolic profile in these patients.To report 23 patients diagnosed with congenital hypopituitarism.Retrospective review of clinical records of 23 patients (12 males) with congenital hypopituitarism, diagnosed during a 21 years period. In a group of 16 patients a molecular study was performed searching for mutations in HESX1, PROP-1 or POUF-1.Short stature was the most frequent sign at the first evaluation, followed by neonatal hypoglycemia and presence of nystagmus, strabismus, atrophic optic nerve or malformations in the middle line showed in CNS imaging, suggesting septo-optic-dysplasia. All male patients diagnosed during neonatal period, exhibited micropenis. CNS images showed isolated hypophyseal hypoplasia or associated to an ectopic neurohypophysis in most patients. No patient in the subgroup subjected to molecular analysis had any of the mutations in the searched genes.The diagnosis of hypopituitarism must be based on clinical grounds, especially when hypoglycemia, prolonged jaundice, micropenis or midline alterations are found in the neonatal period.

Identification and Analysis of Prophet of Pit-1-Binding Sites in Human Pit-1 Gene

Prophet of Pit-1 (Prop1) is a transcription factor that regulates Pit-1 gene expression. Because Pit-1 regulates the differentiation of pituitary cells and the expressions of GH, prolactin and TSHbeta genes, Prop1 mutation results in combined pituitary hormone deficiency in humans. However, Prop1-binding sites in human Pit-1 gene and the mechanism leading to combined pituitary hormone deficiency have remained unclear. In this study, we identified and analyzed Prop1-binding elements of the human Pit-1 gene. Prop1 stimulated the expression of the reporter plasmid containing Pit-1 gene from translation start site to -1340 dose dependently in GH3 cells. The activation by Prop1 was observed in GH3 and TtT/GF cells but not COS7, HeLa, JEG3, and HuH7 cells. Deletion analysis of Pit-1 gene showed that the Prop1-responsive elements were present within the -257-bp region. Within the -257-bp region, there are four elements similar to consensus sequence of paired-like transcription factors. Because Prop1 is a member of paired-like transcription factors, we assessed the elements. EMSA and transient transfection assay using the mutation of the elements revealed that the element from -63 to -53 (the proximal Prop1 binding element) was essential to Prop1-binding and Prop1-induced activation of Pit-1 reporter plasmid. A region at -8kb of human Pit-1 gene is similar to the distal region containing Prop1-binding elements in mouse Pit-1 gene. We showed the region functioned as an enhancer. Furthermore, chromatin immunoprecipitation assay showed that the proximal element could bind Prop1 in vivo cultured cells. Taken together, these findings indicated the novel functioning binding elements of Prop1 in human Pit-1 gene.

Déficit hypophysaire combiné multiple : aspects cliniques et génétiques

DefinitionCongenital hypopituitarism is characterized by multiple pituitary hormone deficiency, including somatotroph, thyrotroph, lactotroph, corticotroph or gonadotroph deficiencies, due to mutations of pituitary transcription factors involved in pituitary ontogenesis. IncidenceCongenital hypopituitarism is rare compared with the high incidence of hypopituitarism induced by pituitary adenomas, transsphenoidal surgery or radiotherapy. The incidence of congenital hypopituitarism is estimated to be between 1:3000 and 1:4000 births. Clinical signsClinical presentation is variable, depending on the type and severity of deficiencies and on the age at diagnosis. If untreated, main symptoms include short stature, cognitive alterations or delayed puberty. DiagnosisA diagnosis of combined pituitary hormone deficiency (CPHD) must be suspected when evident causes of hypopituitarism (sellar tumor, postsurgical or radioinduced hypopituitarism…) have been ruled out. Clinical, biological and radiological work-up is very important to better determine which transcription factor should be screened. Confirmation is provided by direct sequencing of the transcription factor genes. AetiologyCongenital hypopituitarism is due to mutations of several genes encoding pituitary transcription factors. Phenotype varies with the factor involved: PROP1 (somatolactotroph, thyrotroph, gonadotroph and sometimes corticotroph deficiencies; pituitary hyper and hypoplasia), POU1F1 (somatolactotroph and thyrotroph deficiencies, pituitary hypoplasia), HESX1 (variable pituitary deficiencies, septo-optic dysplasia), and less frequently LHX3 (somatolactotroph, thyrotroph and gonadotroph deficiencies, limited head and neck rotation) and LHX4 (variable pituitary deficiencies, ectopic neurohypophysis, cerebral abnormalities). ManagementAn appropriate replacement of hormone deficiencies is required. Strict follow-up is necessary because patients develop new deficiencies (for example late onset corticotroph deficiency in patients with PROP1 mutations). Genetic counsellingType of transmission varies with the factor and the mutation involved (recessive transmission for PROP1 and LHX3, dominant for LHX4, autosomal or recessive for POU1F1 and HESX1). PrognosisIt is equivalent to patients without pituitary deficiencies if treatment is started immediately when diagnosis is confirmed, and if a specialized follow-up is performed.

High Prevalence of Pituitary Magnetic Resonance Abnormalities and Gene Mutations in a Cohort of Brazilian Children with Growth Hormone Deficiency and Response to Treatment

Data were retrospectively collected from 69 Brazilian patients (45 boys) with growth hormone deficiency (GHD) who received exogenous growth hormone (GH) for a median duration of 4 years (range 1-13 years). Forty-two patients had multiple pituitary hormone deficiencies and 27 had isolated GHD. Peak GH was < 7 ng/ml (IRMA) or < 3.2 ng/ml (IFMA) after two stimulation tests. Therapy was started at median age of 10.0 years (range 2.2-21.6 years), bone age of 5.8 years (0.5-13.5 years) and height standard deviation score -4.4 (range -9.3 to -1.6). MRI revealed pituitary abnormalities in 87% of patients. Homozygous mutations in PROP-1, GHRH-R, GH-1 or HESX-1 genes were found in 12 patients. Mean height velocities were 3.3 pretreatment and 10.3, 7.8, 7.4 and 6.4 cm/yr, respectively, during 1-4 years of treatment with GH. In conclusion, the high prevalence (96%) of genetic and/or pituitary abnormalities probably reflects the stringent diagnostic criteria used, and GH replacement resulted in significant catch-up growth.

Molecular analysis of PROP1, PIT1, HESX1, LHX3, and LHX4 shows high frequency of PROP1 mutations in patients with familial forms of combined pituitary hormone deficiency

Combined Pituitary Hormone Deficiency (CPHD) is a prevalent disease in Neuroendocrinology services. The genetic form of CPHD may originate from mutations in pituitary transcription factor (PTF) genes and the pituitary image in these cases may give a clue of what PTF is most probably mutated: defects in LHX4 are usually associated with ectopic posterior pituitary (EPP); defects in LHX3, PIT1, and PROP1, with normally placed posterior pituitary (NPPP); HESX1 mutations are associated with both. To identify mutations in PTF genes in patients with idiopathic hypopituitarism followed in our service, based on the presence or absence of EPP on sellar MRI. Forty patients with idiopathic hypopituitarism (36 families, 9 consanguineous), followed in the Neuroendocrinology Outpatient Clinic of UNIFESP, Brazil, were submitted to sequencing analyses of PTF genes as follows: LHX3, HESX1, PIT1, and PROP1 were sequenced in patients with NPPP (26/40) and HESX1 and LHX4 in patients with EPP (14/40). We identified only PROP1 mutations in 9 out of 26 patients with CPHD and NPPP (35%). Since eight of them came from 4 consanguineous families, the prevalence of PROP1 mutations was higher when only consanguineous families were considered (44%, 4/9). At the end of the study, we decided to sequence PROP1 in patients with EPP, just to confirm that they were not candidates for PROP1 mutations. No patients with EPP had PROP1 or other PTF mutations. Patients with idiopathic CPHD and NPPP, born from consanguineous parents, are the strong candidates for PROP1 mutations. Other developmental gene(s) may be involved in the genesis of idiopathic hypopituitarism associated with EPP.

Combined Pituitary Hormone Deficiency and PROP-1 Mutation in Two Siblings: A Distinct MR Imaging Pattern of Pituitary Enlargement

Mutations of the PROP-1 gene are the most frequent genetic defect in patients with combined pituitary hormone insufficiency. We present the cases of 2 siblings with PROP-1 mutations whom we observed longitudinally. Their initial pituitary MR imaging examinations showed identical findings: an enlarged adenohypophysis, with striking hypointensity on T2-weighted images and slight hyperintensity on T1-weighted images. In one of the children, the follow-up MR imaging obtained 3 years after hormonal replacement revealed a decrease in the size of the anterior pituitary lobe.