Juvenile panhypopituitarism in a dog - what are the therapeutic challenges?

Background: Juvenile panhypopituitarism is an endocrinopathy that affects young dogs and must be differentiated from other causes of height disorders, as one could have a deficiency of one or more adenohypophysis hormones, besides growth hormone. Diagnosis consists of excluding endocrine and non-endocrine causes. Treatment requires administration of heterologous porcine growth hormone or progestins, as well as supplementing other hormones that are deficient in the circulation. The prognosis for these patients tends to be unfavorable and they have a shorter life expectancy. The present case aimed to report the therapeutic challenges in a dog diagnosed with juvenile panhypopituitarism. Case: This study presents the case of a 6-month-old crossbred Labrador/Brazilian Fila dog, not neutered, 6.7 kg of body weight (body condition score 5/9), with a growth disorder and persistence of the puppy coat, when compared to other members of the same litter. During inspection, it was possible to observe an undersized dog and soft puppy coat, besides no bone irregularities or joint tenderness was noted. The other physical examination parameters were within the normal range for the species. No changes in complete blood count and only increases in urea, cholesterol and alkaline phosphatase activity were observed. Thyroid and abdominal ultrasound (US) examination did not reveal any remarkable changes. After serum dosage of insulin-like growth factor, thyroxine, thyrostimulating hormone, and cortisol, the patient was diagnosed with juvenile panhypopituitarism and underwent therapy with medroxyprogesterone and thyroid hormone supplementation. Monitoring was instituted at intervals of 3, 6, and 12 weeks, and currently every 3 or 4 months and the IGF-1 values normalized after 6 months with. After 8 months of therapy, the patient had good body growth and bone mineralization compared to the time of diagnosis. However, skeletal development was completed only 12 months after hormone replacement, accompanied by the presence of vertebral osteophytes and coxofemoral osteoarticular alterations. Considering chronic use of progestins, ovariosalpingohysterectomy (OSH) was recommended, but for personal reasons, the owners chose to do not submit her to surgery. After 18 months of treatment, the dog starts to exhibit prostration, selective appetite, and increased abdominal volume. After imaging exam, she was forwarded for OSH, due to consistent findings of pyometra. Subsequently, even the supervision of possible comorbidities involved in the chronic use of progestins was maintained at half-yearly intervals, the bitch returned to the service with skin thickening, increased limb volume, and macroglossia after 60 months of therapy. At this point IGF-1 values were higher when compared to the previous measurements and the application of medroxyprogesterone was suspended. Its supplementation was reintroduced only after 8 months when IGF-1 was significantly reduced. To date, the patient is close to 6 years of age and with a good quality of life. Discussion: The greatest therapeutic challenge for these patients involves dealing with the adverse effects of progestins, mainly related to reproductive disorders and alopecia at the application site, as well as maintaining adequate hormone replacement in order to avoid hypersomatotropism. Although longevity is lower in these individuals, the patient in this report has achieved 6 years of age and has had an excellent quality of life so far.

Two novel heterozygous missense variations within the GLI2 gene in two unrelated Argentine patients.

Several heterozygous GLI2 gene mutations have been reported in patients with isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD) with or without other malformations. The primary aim of this study was to analyze the presence of GLI2 gene alterations in a cohort of patients with IGHD or MPHD and ectopic/absent posterior pituitary. The coding sequence and flanking intronic regions of GLI2 gene were amplified and directly sequenced from gDNA of 18 affected subjects and relatives. In silico tools were applied to identify the functional impact of newly found variants (Polyphen2, SIFT, Mutation Taster). We identified two novel heterozygous missense variations in two unrelated patients, p.Arg231Gln and p.Arg226Leu, located in the repressor domain of the protein. Both variations affect highly conserved amino acids of the Gli2 protein and were not found in the available databases. In silico tools suggest that these variations might be disease causing. Our study suggests that the GLI2 gene may be one of the candidate genes to analyze when an association of pituitary hormone deficiency and developmental defects in posterior pituitary gland. The highly variable phenotype found suggests the presence of additional unknown factors that could contribute to the phenotype observed in these patients.

Two novel heterozygous missense variations within the GLI2 gene in two unrelated argentine patients / Two novel heterozygous missense variations within the GLI2 gene in two unrelated Argentine patients

Several heterozygous GLI2 gene mutations have been reported in patients with isolated GH deficiency (IGHD) or multiple pituitary hormone deficiency (MPHD) with or without other malformations. The primary aim of this study was to analyze the presence of GLI2 gene alterations in a cohort of patients with IGHD or MPHD and ectopic/absent posterior pituitary. The coding sequence and flanking intronic regions of GLI2 gene were amplified and directly sequenced from gDNA of 18 affected subjects and relatives. In silico tools were applied to identify the functional impact of newly found variants (Polyphen2, SIFT, Mutation Taster). We identified two novel heterozygous missense variations in two unrelated patients, p.Arg231Gln and p.Arg226Leu, located in the repressor domain of the protein. Both variations affect highly conserved amino acids of the Gli2 protein and were not found in the available databases. In silico tools suggest that these variations might be disease causing. Our study suggests that the GLI2 gene may be one of the candidate genes to analyze when an association of pituitary hormone deficiency and developmental defects in posterior pituitary gland. The highly variable phenotype found suggests the presence of additional unknown factors that could contribute to the phenotype observed in these patients.

Mutaciones heterocigotas en el gen GLI2 fueron previamente comunicadas como causa de déficit aislado de hormona de crecimiento (IGHD) o déficit múltiple de hormonas hipofisarias (MPHD), con o sin otras malformaciones. El objetivo del estudio fue analizar la presencia de alteraciones en el gen GLI2 en un grupo de pacientes con IGHD o MPHD acompañado de neurohipófisis ectópica o ausente. La secuencia codificante y las regiones intrónicas flanqueantes del gen GLI2 fueron amplificadas y secuenciadas de manera directa a partir de ADN genómico extraído de sangre periférica proveniente de 18 sujetos afectados y sus familiares. Se utilizaron herramientas informáticas para predecir el impacto funcional de las nuevas variantes encontradas (Polyphen2, SIFT, Mutation Taster). Identificamos dos nuevas variantes heterocigotas con pérdida de sentido en dos pacientes no relacionados, p.Arg231Gln y p.Arg226Leu, localizadas en el dominio represor de la proteína. Estas variantes afectan aminoácidos altamente conservados en la secuencia proteica de GLI2 y no se encuentran informadas en las bases de datos disponibles. Las herramientas informáticas utilizadas sugieren que estas variantes pueden ser la causa del desarrollo de la enfermedad. Nuestro resultados indican que el gen GLI2 es uno de los genes candidatos a estudiar cuando existe una asociación entre déficit de hormonas hipofisarias y alteraciones en el desarrollo de la neurohipófisis. Se sugiere la existencia de otros factores adicionales que podrían contribuir a la variabilidad del fenotipo observado.

Severe congenital hypopituitarism with low prolactin levels and age-dependent anterior pituitary hypoplasia: a clue to a PIT-1 mutation.

A 20-month-old boy presented with severe congenital growth hormone, thyrotropin, and prolactin deficiencies resulting from a de novo mutation of the PIT-1 gene. This form of congenital hypopituitarism should be suspected if pituitary anatomy is normal, especially if prolactin levels are low and, in boys, if the external genitalia are normal. Pituitary atrophy appears to be an age-dependent phenomenon in this condition.

Nasal pyriform aperture stenosis and absence of the anterior pituitary gland: report of two cases.

We describe two female infants with congenital nasal pyriform aperture stenosis and severe pituitary insufficiency. The anterior pituitary gland was undetectable with magnetic resonance imaging. Consanguinity of parents in both cases suggests autosomal recessive inheritance of this disorder. An early fetal developmental defect may explain this syndrome, which affects midline craniofacial structures. In patients with congenital pyriform aperture stenosis, magnetic resonance imaging of the brain and endocrine investigations should be performed for rapid diagnosis and treatment of the latter to avoid major neurologic complications.

MRI of congenital pituitary insufficiency.

We compared 1.5 T magnetic resonance (MR) image findings in 193 patients with congenital pituitary insufficiency. One hundred and thirty nine of the MR studies were obtained in patients who had isolated growth hormone deficiency (GHD). Other fifty-four patients had multiple pituitary hormone deficiency (MPHD). On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In fifty-four patients, the high-intensity of the posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in fifty-one patients. This high-intensity area is the newly formed ectopic posterior lobe, which also secrets anti-diuretic hormone just as the posterior lobe would. MR imaging can demonstrate the transection of the pituitary stalk and the formation of the ectopic lobe, revealing to be a usefull diagnostic tool in the definition of the type of alteration in growth defects of endocrine origin.

Magnetic resonance imaging in the diagnosis of growth hormone deficiency.

Forty-six patients with idiopathic growth hormone deficiency were examined by magnetic resonance imaging at a mean (+/- SEM) age of 9 +/- 1 years (range 15 days to 20 years). They were classified into two groups according to MRI images: group 1 (n = 29) had pituitary stalk interruption syndrome and group 2 (n = 17) had normal pituitary anatomy. All patients with pituitary stalk interruption had a pituitary height at less than -2 SD for age; three had no visible anterior pituitary lobe. By contrast, the pituitary height was less than normal in only 10 patients (60%) with normal pituitary anatomy. Growth hormone deficiency was transient in one of the seven patients with normal pituitary anatomy and height. The group with pituitary stalk interruption had the first symptom of growth hormone deficiency at an earlier age (2.8 +/- 0.6 vs 5.5 +/- 1.2 years; p less than 0.001), were of smaller stature (-4 +/- 0.2 vs -3 +/- 0.2 SD; p less than 0.01) and had lower GH peak response to provocative testing (3 +/- 0.4 vs 5 +/- 0.5 ng/ml; p less than 0.001) than did the group with normal pituitary anatomy. Their pituitary gland was also shorter (2.5 +/- 0.2 vs 3.5 +/- 0.2 mm; p less than 0.01). All the patients with multiple pituitary deficiencies except one (n = 19) belonged to this group. One girl with pituitary stalk interruption and deficiencies in growth hormone and thyroid-stimulating hormone had advanced central precocious puberty. We conclude that the evaluation of the shape and height of the pituitary gland by MRI is an additional tool for the diagnosis of growth hormone deficiency. The presence of pituitary stalk interruption confirms this diagnosis and is predictive of multiple anterior pituitary deficiencies. The lack of a significant increase in perinatal abnormalities in this group and the association of pituitary stalk interruption with microphallus and with facial or sella abnormalities suggest that this appearance may have an early antenatal origin. The finding of a familial case of pituitary stalk interruption suggests a genetic origin.

A familial syndrome of isolated "aplasia" of the anterior pituitary. Diagnostic studies and treatment in the neonatal period.

A male newborn infant developed hypoglycemia, collapsed, and convulsed at eight hours of age. The diagnosis of pituitary "aplasia" was suspected, because of a previously affected female sibling, and treatment with glucocorticoids was instituted. Diagnostic studies revealed a deficiency of thyrotropin, growth hormone, and prolactin. He is now six months of age and is thriving on replacement therapy. Analysis of previous reports of this entity indicates that isolated "aplasia" of the anterior pituitary is a genetic syndrome with an autosomal recessive mode of transmission. The course in this patient suggests that this disorder, if diagnosed, is amenable to therapy.