Abnormal hypothalamic/posterior pituitary development appears to be a major determinant of pituitary stalk interruption syndrome (PSIS). The observation of familial cases and associated congenital abnormalities suggests a genetic basis. Single-gene mutations explain less than 5% of the cases, and whole exome sequencing has shown heterogeneous results. The present study aimed to assess copy number variation (CNV) using array-based comparative genomic hybridization (aCGH) in patients with non-syndromic PSIS and comprehensively review data from the literature on CNV analysis in congenital hypopituitarism (CH) patients. Twenty-one patients with sporadic CH from our outpatient clinics presented with ectopic posterior pituitary (EPP) and no central nervous system abnormalities on magnetic resonance image (MRI) or any other malformations on physical examination at presentation were enrolled in the study. aCGH using a whole-genome customized 400K oligonucleotide platform was performed in our patients. For the literature review, we searched for case reports of patients with CH and CNV detected by either karyotype or aCGH reported in PubMed up to November 2021. Thirty-five distinct rare CNVs were observed in 18 patients (86%) and two of them (6%) were classified as pathogenic: one deletion of 1.8 Mb in chromosome 17 (17q12) and one deletion of 15 Mb in chromosome 18 (18p11.32p11.21), each one in a distinct patient. In the literature review, 67 pathogenic CNVs were published in 83 patients with CH, including the present study. Most of these patients had EPP (78% out of the 45 evaluated by sellar MRI) and were syndromic (70%). The most frequently affected chromosomes were X, 18, 20 and 1. Our study has found that CNV can be a mechanism of genetic abnormality in non-syndromic patients with CH and EPP. In future studies, one or more genes in those CNVs, both pathogenic and variant of uncertain significance, may be considered as good candidate genes.

BACKGROUND: Xq27.1 duplication encompassing SOX3 has been implicated in the aetiology of X-linked hypopituitarism associated with intellectual disability and neural tube defects. We describe the largest case series to date of 5 unrelated patients with SOX3 duplication with a variable clinical phenotype, including the smallest reported SOX3 duplication.
METHODS: Five male patients who presented with congenital hypopituitarism (CH) were identified to have Xq27.1 duplication encompassing SOX3. The size of the duplication ranged from 323.8 kb to 11 Mb. The duplication was maternally inherited or de novo in 2 patients each (and of unknown inheritance in 1 patient). The age at presentation was variable. Three patients had multiple pituitary hormone deficiencies, whereas 2 patients had isolated growth hormone deficiency. All patients had micropenis and/or small undescended testes. Structural pituitary and/or other midline cranial abnormalities (callosal hypogenesis/absence of the septum pellucidum) were present in all patients. Two patients had a neural tube defect in addition to CH.
CONCLUSIONS: This is the largest series reported to date of unrelated patients with CH in association with Xq27.1 duplication encompassing SOX3. The clinical phenotype is variable, which may be due to genetic redundancy or other unknown aetiological factors. We have expanded the phenotypic spectrum through description of the smallest Xq27.1 duplication (323.8 kb) with CH reported to date, as well as a second family with CH and a neural tube defect.

Background Persistent hypoglycemia (PH) beyond 3 days of life warrants investigation which includes a critical sample. We report our case series of five neonates who presented with PH as the first sign of congenital hypopituitarism. Design This is a case series. Methods/Results This is a case series of five neonates evaluated at our academic institution in a 3-year period (2013-2016), who presented with persistent severe hypoglycemia and were subsequently diagnosed with congenital hypopituitarism. All neonates were full term (mean gestational age 39.8 ± 1.4 weeks) born by caesarian section with a mean weight of 3.5 ± 0.16 kg and a mean length of 51.2 ± 1.2 cm at birth. All five neonates had PH beyond 3 days with an average blood glucose (BG) <35 mg/dL at presentation, requiring a mean glucose infusion rate (GIR) of 7.22 ± 1.98 mg/kg/min. The average BG during the critical sample was 42 ± 0.16 mg/dL (three patients). The mean duration of requirement of the glucose infusion was 6.2 ± 3 days during the immediate neonatal period. Diagnosis of the hypopituitarism took 2-52 days from the initial presentation of hypoglycemia. Besides growth hormone (GH) deficiency, cortisol deficiency was diagnosed in all the five neonates. Neuroimaging findings in all the neonates were consistent with pituitary stalk interruption syndrome (hypoplastic anterior pituitary, ectopic posterior pituitary [EPP] and interrupted pituitary stalk). Conclusions Hypoglycemia is a common metabolic complication affecting an infant in the immediate neonatal period. Delay in the diagnosis of hypopituitarism presenting as hypoglycemia is the result of the lack of awareness among neonatologists and/or pediatricians. We propose that providers be cognizant that PH can be the only presentation of hypopituitarism in the neonatal period. Therefore, having a high index of suspicion about this condition can avoid a delay in the evaluation, diagnosis and treatment of hypopituitarism.