Insufficient adrenarche in patients with combined pituitary hormone deficiency caused by a PROP-1 gene defect

Therapy-Induced Growth and Sexual Maturation in a Developmentally Infantile Adult Patient with a PROP1 Mutation

BACKGROUND

Hypopituitarism as a result of PROP1 (prophet of PIT1) mutation represents the most common genetic cause of combined deficiency of pituitary hormones and due to growth retardation it is typically diagnosed in childhood.

CASE DESCRIPTION

We present a unique case report of a prepubertal woman with growth retardation in whom combined pituitary hormone deficiency [central hypopituitarism, hypogonadism, and growth hormone (GH) deficiency] caused by homozygous mutation c.150delA in the PROP1 gene was diagnosed late in young adulthood due to unfavorable life circumstances. Through cautiously combined GH therapy and sex hormone therapy, she has achieved better than expected height (exceeding predictions based on family height) and sexual maturation, including regular menstrual cycles.

CONCLUSION

Early diagnosis of panhypopituitarism due to PROP1 mutation is essential for successful treatment; however, our case report shows that carefully titrated GH treatment and sex hormone substitution, although initiated in adulthood, enable restoration of physiological growth and sexual development in a hormonally infantile adult woman with a PROP1 mutation.

Two coexisting heterozygous frameshift mutations in PROP1 are responsible for a different phenotype of combined pituitary hormone deficiency

The role of genetic background in childhood-onset combined pituitary hormone deficiency (CPHD) has been extensively studied. The major contributors are the PROP1, POU1F1, LHX3, LHX4 and HESX1 genes coding transcription factors implicated in pituitary organogenesis. The clinical consequences of mutations encompass impaired synthesis of a growth hormone (GH) and one or more concurrent pituitary hormones (i.e. LH, FSH, TSH, PRL). Manifestation of the disorder may vary due to various mutation impacts on the final gene products or an influence of environmental factors during pituitary organogenesis. We describe the clinical and molecular characteristics of two brothers aged 47 and 39 years presenting an uncommon manifestation of congenital hypopituitarism. Sequencing of the PROP1, POU1F1, LHX3, LHX4 and HESX1 genes was performed to confirm the genetic origin of the disorder. A compound heterozygosity in the PROP1 gene has been identified for both probands. The first change represents a mutational hot spot (c.150delA, p.R53fsX164), whereas the second is a novel alteration (p.R112X) that leads to protein disruption. Based on precise genetic diagnosis, an in silico prediction of a p.R112X mutation on protein architecture was performed. The resulting clinical phenotype was surprisingly distinct compared to most patients with genetic alterations in PROP1 reported in the current literature. This may be caused by a residual activity of a newly identified p.R112X protein that preserves over 70 % of the homeodomain structure. This examination may confirm a key role of a DNA-binding homeodomain in maintaining PROP1 functionality and suggests a conceivable explanation of an unusual phenotype.

PROP-1 gene mutations in a 63-year-old woman presenting with osteoporosis and hyperlipidaemia

PROP-1 gene mutations have been reported as a cause of combined pituitary hormone deficiency. Physical and hormonal phenotypes of affected individuals are variable. We report a 63-year-old female who presented with osteoporosis. She was short, did not enter puberty spontaneously and had primary amenorrhea. Biochemical evaluation revealed secondary hypothyroidism and mixed hyperlipidaemia, while dynamic testing of pituitary function was diagnostic of hypopituitarism. Bone density in the lumbar spine disclosed osteoporosis. DNA analysis showed that the patient was homozygote for the R73H mutation of the PROP-1 gene. The unfavourable long-term course of an untreated patient with PROP-1 gene mutation emphasizes the need for early aetiologic classification and proper management and follow-up of patients with short stature and/or disturbances of pubertal development.

Adrenarche and polycystic ovary syndrome: a tale of two hypotheses

Polycystic ovary syndrome (PCOS) is an extremely common endocrine disorder affecting young women, with the potential for both reproductive and non-reproductive adverse outcomes. While oligomenorrhea, hyperandrogenism, and cystic ovarian morphology are recognized characteristics of this syndrome, the origin of these disturbances is not always apparent. During normal growth and development, adrenarche, the prepubertal onset of adrenal androgen secretion, results phenotypically in pubarche. Gonadarche, which is the ovarian response to gonadotropin releasing hormone-mediated gonadotropin secretion, also occurs, leading to reproductive competence, namely the establishment of ovulatory cycles, repeatedly. In this mini-review, an overview of adrenarche and gonadarche are presented, followed by two hypotheses. The first describes an evolutionary role for adrenarche: an advantage in the attainment of reproductive competence. The second proposes that the path to PCOS be viewed from a developmental perspective, namely, that PCOS is a maladaptation of the processes that lead to reproductive competence in women. Its defining characteristics of oligomenorrhea, hyperandrogenism, and cystic ovarian morphology are the final common pathway of multiple possible derangements. Elucidating and understanding these maladaptive processes will be the key to future endeavors at prevention and treatment of this common reproductive disorder.

Combined pituitary hormone deficiency (CPHD) due to a complete PROP1 deletion

OBJECTIVE

PROP1 mutations are the most common cause of genetic combined pituitary hormone deficiency (CPHD). The aim of this study was to investigate the PROP1 gene in two siblings with CPHD.

DESIGN

Pituitary function and imaging assessment and molecular analysis of PROP1.

PATIENTS

Two siblings, born to consanguineous parents, presented with GH deficiency associated with other pituitary hormone deficiencies (TSH, PRL and gonadotrophins). The male sibling also had an evolving cortisol deficiency.

METHODS

Pituitary size was evaluated by magnetic resonance imaging (MRI). PROP1 gene analysis was performed by polymerase chain reaction (PCR), automatic sequencing and Southern blotting. Amplification of sequence tag sites (STS) and the Q8N6H0 gene flanking PROP1 were performed to define the extension of PROP1 deletion.

RESULTS

MRI revealed a hypoplastic anterior pituitary in the girl at 14 years and pituitary enlargement in the boy at 18 years. The PROP1 gene failed to amplify in both siblings, whereas other genes were amplified. Southern blotting analysis revealed the PROP1 band in the controls and confirmed complete PROP1 deletion in both siblings. The extension of the deletion was 18.4 kb. The region flanking PROP1 contains several Alu core sequences that might have facilitated stem-loop-mediated excision of PROP1.

CONCLUSIONS

We report here a complete deletion of PROP1 in two siblings with CPHD phenotype.

Somatotropic and gonadotropic axes linkages in infancy, childhood, and the puberty-adult transition

Integrative neuroendocrine control of the gonadotropic and somatotropic axes in childhood, puberty, and young adulthood proceeds via multiple convergent and divergent pathways in the human and experimental animal. Emerging ensemble concepts are required to embody independent, parallel, and interacting mechanisms that subserve physiological adaptations and pathological disruption of reproduction and growth. Significant advances in systems biology will be needed to address these challenges.

Absent or Delayed Adrenarche in Pit-1/POU1F1 Deficiency

Mutations of the PIT1/POU1F1 gene are responsible for a rare variant of anterior hypopituitarism, including deficiency of growth hormone, prolactin and thyrotropin. In 8 ethnically diverse POU1F1-deficient patients (4 different mutations) with normal circulating levels of cortisol and adrenocorticotropic hormone, and with spontaneous onset and progression of puberty, we observed an absence or delay of adrenarche (median circulating dehydroepiandrosterone-sulfate -6.2 SD); in each of the 4 postmenarcheal females, pubarche (i.e. appearance of pubic hair) was also absent or delayed. The absence/delay of adrenarche in POU1F1-deficient patients and the absence/delay of pubarche in POU1F1-deficient females suggest that a POU1F1-dependent factor contributes to the normal development of adrenarche and female pubarche.

Ovulation induction and successful pregnancy outcome in two patients with Prop1 gene mutations

OBJECTIVE

To describe ovulation induction and pregnancy outcome in a unique model of genetically determined combined pituitary hormone deficiency (CPHD), with respect to the necessity for GH substitution therapy.

DESIGN

Case report.

SETTING

Academic units.

PATIENT(S)

Two patients with childhood onset of CPHD (GH, PRL, TSH, LH, FSH) caused by a genetic defect (GA296del mutation) of the Prop1 gene.

MAIN OUTCOME MEASURE(S)

Ovulation, pregnancy outcome, and fetal growth.

RESULT(S)

Successful pregnancy outcome and delivery of normal, full-term newborns were achieved in both patients with the use of gonadotropins and L-T(4). Growth hormone supplementation was not necessary. No lactation was observed.

CONCLUSION(S)

Patients with Prop1 gene mutations constitute a unique model for studying the role of GH and PRL in ovulation, pregnancy, and fetal growth. Our data indicate that for women with CPHD, ovulation and pregnancy are possible with a classic regimen for hypogonadotropic hypogonadism, without the need for GH substitution therapy.

DAX1 and its network partners: exploring complexity in development

DAX1 encoded by NR0B1, when mutated, is responsible for X-linked adrenal hypoplasia congenita (AHC). AHC is due to failure of the adrenal cortex to develop normally and is fatal if untreated. When duplicated, this gene is associated with an XY sex-reversed phenotype. DAX1 expression is present during development of the steroidogenic hypothalamic-pituitary-adrenal-gonadal (HPAG) axis and persists into adult life. Despite recognition of the crucial role for DAX1, its function remains largely undefined. The phenotypes of patients and animal models are complex and not always in agreement. Investigations using cell lines have proved difficult to interpret, possibly reflecting cell line choices and their limited characterization. We will review the efforts of our group and others to identify appropriate cell lines for optimizing ex vivo analysis of NR0B1 function throughout development. We will examine the role of DAX1 and its network partners in development of the hypothalamic-pituitary-adrenal/gonadal axis (HPAG) using a variety of different types of investigations, including those in model organisms. This network analysis will help us to understand normal and abnormal development of the HPAG. In addition, these studies permit identification of candidate genes for human inborn errors of HPAG development.

Low TSH congenital hypothyroidism: identification of a novel mutation of the TSH beta-subunit gene in one sporadic case (C85R) and of mutation Q49stop in two siblings with congenital hypothyroidism

Isolated congenital hypothyroidism resulting from mutation of the TSH beta-subunit gene, has rarely been reported. In the present article, we report a new mutation (C85R) in exon 3 of the TSH beta-subunit gene in one sporadic case and the mutation Q49stop in two siblings with congenital hypothyroidism. The novel mutation is a T to C transition at codon 85, resulting in a change of cysteine to arginine (C85R) of the ss-subunit. Because the cysteine residues of all glycoproteins are highly conserved, this mutation is expected to result in conformational changes of the ss-subunit, rendering it incapable to form a functional heterodimer with the alpha-subunit. The second mutation described is a C to T transition resulting in a premature stop at codon 49 (Q49stop), leading to the formation of a truncated protein. Although the two siblings reported herein carried the same mutation, they had slightly modified clinical and biochemical phenotype. The mutation C85R and the previously described E11stop have, thus far, exclusively been detected in Greek patients. The Q49stop mutation initially detected in Greek patients was subsequently identified in an Egyptian girl and most recently in two Turkish siblings. These three reports possibly indicate the presence of a mutational hot spot on the TSH beta-subunit gene. Hence, with the novel mutation herein reported, a total of five mutations of the TSH beta-subunit gene are recognized as a cause of low-TSH congenital hypothyroidism worldwide.