Brain Magnetic Resonance Imaging as First-Line Investigation for Growth Hormone Deficiency Diagnosis in Early Childhood.

BACKGROUND/AIMS: The diagnosis of growth hormone (GH) deficiency (GHD) in infancy and early childhood is not straightforward. GH stimulation tests are unsafe and unreliable in infants, and normative data are lacking. This study aims to investigate whether brain magnetic resonance imaging (MRI) may replace GH stimulation tests in the diagnosis of GHD in children younger than 4 years. METHODS: We examined a retrospective cohort, with longitudinal follow-up, of 68 children consecutively diagnosed with GHD before the age of 4 years. The prevalence of hypothalamic-pituitary (HP) alterations at MRI and the associations with age and either isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) were assessed. RESULTS: The prevalences of IGHD and MPHD were 54.4 and 45.6%, respectively. In the first group, brain MRI showed abnormalities in 83.8%: isolated pituitary hypoplasia in 48.7% and complex defects in 35.1%. In patients with MPHD, MRI showed complex alterations in 100%. All children younger than 24 months showed HP MRI abnormalities, regardless of the diagnosis. Complex defects were found in 94% of patients younger than 12 months and in 75% of patients between 13 and 24 months. CONCLUSION: Our data suggest that brain MRI may represent the first-line investigation for diagnosing GHD in infancy and early childhood.

Longitudinal hormonal evaluation in a patient with disorder of sexual development, 46,XY karyotype and one NR5A1 mutation.

Steroidogenic factor 1 (encoded by the NR5A1 gene) is a critical regulator of reproduction, controlling transcription of key genes involved in sexual dimorphism. To date, NR5A1 variants have been found in individuals with a 46,XY karyotype and gonadal dysgenesis, as well as with a wide spectrum of genital anomalies and, in some patients, with adrenal insufficiency. We describe evolution of gonadal function, from the neonatal period to puberty, in a patient with a 46,XY karyotype, a disorder of sexual development, and a mutation (c.691_699dupCTGCAGCTG) in the NR5A1 gene. The patient, ascertained at birth due to ambiguous genitalia, showed normal values of plasma testosterone in the late neonatal period. Evaluation of the hormonal profile over time indicated severe tubular testicular hypofunction suggestive for a 46,XY disorder of gonadal development. A comprehensive review of published reports of 46,XY and disordered sexual development related to the NR5A1 gene confirmed the clinical and hormonal variability in patients with NR5A1 mutations. Analysis of multiple data allowed us to define the most common features associated with NR5A1 mutations. We further confirmed the indication to perform NR5A1 screening in patients with 46,XY karyotype and disordered sexual development even when Müllerian structures appear to be absent and plasma testosterone levels are within the normal range for age.

Three unrelated patients with congenital anterior pituitary aplasia and a characteristic physical and neuropsychological phenotype: a new syndrome?

Anterior pituitary aplasia (APA) is a very rare cause of congenital-onset multiple pituitary hormone deficiency (CO-MPHD). We report on molecular analysis and clinical follow-up of three previously reported cases of APA [Scommegna et al., 2004], who share a characteristic physical and neuropsychological profile. Mutation analysis of genes encoding transcription factors involved in pituitary development (PROP1, POUF1, HESX1, LHX3, and LHX4) did not demonstrate a any mutation. In order to identify the genetic cause underlying the phenotypes we performed an array-based comparative genomic hybridization (array-CGH), which showed a cryptic interstitial deletion of 9p (200 kb), including the TEK and MOBKL2B, in one patient. Although an apparently identical deletion was carried by the clinically normal father, we assumed that the patient's phenotype might be due to a recessive mutation in the other allele. However, sequence analysis of exons and splice junctions of these genes did not detect pathogenic or predisposing variants in the three patients. We suggest that the constellation of clinical signs in these patients constitutes a previously undescribed syndrome, whose genetic cause has yet to be identified.

Growth hormone deficiency after localized ganglioneuroblastoma: A case report.

Growth hormone deficiency (GHD) related to standard dose chemotherapy has rarely been described. We report on a case of localized ganglioneuroblastoma treated by carboplatin/etoposide for 2 courses and surgery, which developed a serious GHD after 56 months. At present, the child is growing on by GH replacement therapy. We discuss about the hypothesis that GHD may be related to chemotherapy and we report a review of previous published cases.

Neonatal identification of pituitary aplasia: a life-saving diagnosis. Review of five cases.

BACKGROUND: Neonatal onset hypopituitarism is a life-threatening, potentially treatable endocrine disease. A possible cause is congenital absence of the anterior pituitary gland, a condition very rarely reported in the literature. METHODS: A series of 5 cases of children with pituitary aplasia referred to the Centre of Paediatric Endocrinology 'Rina Balducci', Tor Vergata University, Rome, is presented. RESULTS: Major clinical features in our patients were respiratory distress on the first day of life, in spite of uneventful pregnancy, labour and delivery, metabolic acidosis, non-cholestatic jaundice, hypotonia, severe hypoglycaemia, hypogenitalism, and midline defects. Diagnosis was established by endocrine tests during hypoglycaemia and hypothalamic-pituitary MRI scan. Symptoms disappeared soon after replacement therapy was started. CONCLUSION: We stress the importance of performing baseline endocrine tests as soon as possible during hypoglycaemia and MRI of the brain aimed at visualizing the hypothalamic-pituitary area in neonates with hypogenitalism and severe unexplained hypoglycaemia, so that the irreversible neurological and developmental consequences of panhypopituitarism can be prevented by adequate replacement therapy.

Evaluation of anterior pituitary gland volume in childhood using three-dimensional MRI.

BACKGROUND: Three-dimensional MRI (3D-MRI) is a reliable tool for the evaluation of anatomical volumes. Volumetric measurement of the normal anterior pituitary gland in childhood has been performed in the past by 2D-MRI calculations, but has inherent inaccuracies. OBJECTIVE: To obtain accurate normal anterior pituitary gland volume in childhood using 3D-MRI coronal sections. MATERIALS AND METHODS: The anterior pituitary gland was measured using coronal T1-weighted 3D-gradient-echo sequences (section thickness 0.75 mm). The study group was composed of 95 prepubertal children (age range 2 months-10 years) with clinically normal pituitary function and no pituitary or brain abnormalities. RESULTS: A measurement error of 0.2-0.4% was assessed by using a phantom study. Volumetric evaluation of the anterior pituitary gland showed progressive growth of the gland from a mean 131+/-24 mm(3) at 2-12 months, to 249+/-25 mm(3) at 1-4 years and 271+/-29 mm(3) at 5-10 years. CONCLUSIONS: These data may be useful for paediatricians in the evaluation of patients with neuroendocrine diseases, in particular growth hormone deficiency.

Height velocity and IGF-I assessment in the diagnosis of childhood onset GH insufficiency: do we still need a second GH stimulation test?

OBJECTIVE: The diagnosis of GH insufficiency (GHI) in childhood is not straightforward. Our aim was to test the sensitivity and specificity of height velocity (HV), IGF-I, IGFBP-3 and GH stimulation tests alone or in combination in the diagnosis of GHI. DESIGN: A retrospective review of patients with GHI and idiopathic short stature (ISS) diagnosed in our centre and followed up to the completion of linear growth. PATIENTS: Thirty-three GHI children and 56 children with ISS were evaluated. GHI diagnosis was based on fulfilment of anthropometric, endocrine and neuroradiological criteria: stature < or = -2 z-score, delayed bone age (at least 1 year), GH peak response to at least two different provocative tests < 10 micro g/l (20 mU/l), brain MRI positive for hypothalamus-pituitary abnormalities, catch-up growth during the first year of GH replacement therapy > or = 75th centile, peak GH response to a third provocative test after growth completion < 10 micro g/l (20 mU/l). Children with anthropometry resembling that of GHI but with peak GH responses > 10 micro g/l (20 mU/l) were diagnosed as ISS. MEASUREMENTS: All subjects underwent standard anthropometry. GH secretory status was assessed by clonidine, arginine and GHRH plus arginine stimulation tests. IGF-I and IGFBP-3 circulating levels were measured by immunoradiometric assay (IRMA). The following cut-off values were chosen to discriminate between GHI and nonGHI short children: HV < 25th centile over the 6-12 months prior to the initiation of GH therapy, peak GH responses < 10 or < 7 micro g/l (< 20 or < 14 mU/l) and IGF-I and IGFBP-3-values < -1.9 z-score. Sensitivity (true positive ratio) and specificity (true negative ratio) were evaluated. RESULTS: Taking 10 micro g/l (20 mU/l) as the cut-off value, sensitivity was 100% and specificity 57% for GH provocative tests, whereas taking 7 as the cut-off value, sensitivity was 66% and specificity rose to 78%. Sensitivity was 73% for IGF-I and 30% for IGFBP-3 measurement, whilst specificity was 95% for IGF-I and 98% for IGFBP-3 evaluation. HV assessment revealed a sensitivity of 82% and a specificity of 43%. When HV and IGF-I evaluations were used in combination, sensitivity reached 95% and specificity 96%. When both HV and IGF-I are normal (26% of our subjects) GHI may be ruled out, whereas when both the indices are subnormal (23%) GHI is so highly likely that the child may undergo only one GH provocative test and brain MRI and, thereafter, may begin GH therapy without any further test. In case of discrepancy, when IGF-I is normal and HV < 25th centile (44% of children), due to the relatively low sensitivity of IGF-I assessment and low specificity of HV, the patient should undergo GH tests and brain MRI. Finally, in the rare case of HV > 25th centile and subnormal IGF-I-values (7%), due to the high specificity of IGF-I measurement, the child should undergo one provocative test and brain MRI for the high suspicion of GHI. CONCLUSIONS: Our results suggest that a simple assessment of HV and basal IGF-I may exclude or, in association with only one stimulation test, confirm the diagnosis of GH insufficiency in more than half of patients with short stature.