An association with hypopituitarism and 9q subtelomere deletion syndrome

Key Clinical Message Hypopituitarism could have been overlooked so far in the patients with 9q subtelomere deletion syndrome (9qSTDS); thus, further investigations or reevaluation of clinical information, especially hormonal evaluations, are warranted to determine whether hypopituitarism is a rare or relatively common presentation in patients with 9qSTDS.

arched eyebrows, midface hypoplasia, a short nose with upturned nares, a protruding tongue, everted lower lip, and downturned corners of the mouth. 3 In addition, congenital heart defects, epilepsy, and urogenital defects are frequently observed. To the best of our knowledge, however, hypopituitarism with 9qSTDS has not been previously reported. Here, we present the first case of definite hypopituitarism with a 9q34.3 subtelomeric deletion, thus expanding our understanding of the phenotypic features associated with 9qSTDS.

| CASE REPORT
The patient was a 7-year-old Japanese boy born at 38 weeks of gestation after an uncomplicated pregnancy and delivery. His parents were nonconsanguineous and phenotypically normal. He had no family history of pituitary dysfunction. His birth length was 51.0 cm (1.0 SD), and weight was 3.4 kg (0.9 SD). At birth, several dysmorphic features including hypertelorism, synophrys, midface hypoplasia, right preauricular pits, prominent antihelix, short philtrum, and thin upper lip with downturned corners of the mouth were observed. Echography revealed an atrial septal defect and left renal hydronephrosis. An auditory brainstem response examination revealed mild hearing impairment in both ears. The testes were undescended. Neonatal screening levels of thyroid-stimulating hormone (TSH) and free T4 were normal. At the age of 1 years and 5 months, his height was 77.2 cm (−0.9 SD), weight was 8.35 kg (−1.8 SD), and head circumference was 44.6 cm (−1.3 SD), respectively.
He was referred to us at 4 years of age because of his short stature. His height and weight were 87.7 cm (−3.2 SD) and 10.2 kg (−2.7 SD), respectively. He showed micropenis, with a stretched penile length of 2.5 cm. Brain magnetic resonance imaging revealed an anterior pituitary hypoplasia with a visible but thin stalk, as well as an eutopic posterior pituitary gland ( Figure 1). No other abnormalities in the central nervous    The peak of TSH was normal; however, prolonged increase in TSH (20.241 mIU/mL at 120 minutes after TRH administration) indicated hypothalamic hypothyroidism. b Reference data of UK children (younger than 10 y). c Reference data of Japanese 4-year-old boys. d Reference data of Japanese 6-year-old boys. system were found. Hormonal data revealed growth hormone (GH) and TSH deficiencies ( Table 1). The cortisol peak response during the corticotropin-releasing hormone (CRH) test was normal (peak cortisol = 17.3 μg/dL, Ref > 20.0 μg/ dL or increment of 10 μg/dL). A replacement therapy with lthyroxine was started. Replacement therapy with GH was refused by the parents. At the age of 6 years and 4 months, the patient exhibited hypoglycemia without an apparent cause. The blood glucose level was 35 mg/dL when he was admitted to our hospital. Hyperinsulinism was excluded based on the analysis of critical samples (serum insulin levels were below 0.60 μIU/mL). We reevaluated his pituitary function by provocation tests, and an impaired cortisol response was observed during the CRH test (peak cortisol 13.3 μg/dL). He was then diagnosed with central adrenal insufficiency due to adrenocorticotropic hormone (ACTH) deficiency (Table 1), and a replacement therapy with hydrocortisone was started. After starting hydrocortisone therapy, hypoglycemia has not been recorded since. At his last examination at the age of 7 years and 6 months, his height and weight were 106.0 cm (−3.2 SD) and 16.4 kg (−1.8 SD), respectively. Owing to severe psychomotor retardation, he remains wheelchairbound and nonverbal.
Genomic DNA from the patient was subjected to array comparative genomic hybridization with the Agilent 4 × 180 K SurePrint G3 Human CGH Microarray (catalog no. G4449A; Agilent Technologies). We identified a heterozygous 1.3-Mb subtelomeric deletion at 9q34.3 ( Figure 2). Multiplex ligationdependent probe amplification (MLPA) analysis of the parents revealed that this deletion was de novo (data not shown). The list of the deleted genes is provided as Data S1.
The combination of two relatively rare conditions, 9qSTDS and hypopituitarism, led us to perform additional study: whole-exome sequence (WES) to obtain additional genetic information for the etiology of the hypopituitarism. Detailed are described in Data S3. We provide the list of variants of unknown significance (VUS) detected in WES as Data S2. The number of variants remaining after each filtering step is provided in Supplemental Table 1. No mutations were found in the currently known hypopituitarism-related genes (POU1F1, PROP1, HESX1, LHX4, OTX2, SOX2, SOX3, GLI2, PAX6, IGSF1, GPR161, FGF8, KAL1, PROK2R, and LHX3). As one allele was lost for the region of chromosome 9q34.3 in the patient, any mutations in this region in the remained allele could be functionally null. However, we were unable to identify any pathological sequence variations in the genes located in the deleted region. Trio de novo approach using the DNAs from parents was refused.

| DISCUSSION
To the best of our knowledge, this is the first example of a patient presenting with hypopituitarism, harboring a heterozygous 1.3-Mb deletion in 9q34.3. Short stature and genital abnormalities, such as cryptorchidism and micropenis, both of which could be the results of hypopituitarism, are relatively common phenotypes in the patient with 9qSTDS: short stature in 32% and genital abnormalities in 32% of 9qSTDS patients. 4 No 9qSTDS cases evaluated for pituitary functions have been reported; therefore, hypopituitarism with 9qSTDS could have been overlooked so far, and further investigations or reevaluations of clinical information, especially hormonal evaluations, are warranted. It is also of note that the secretion of ACTH gradually decreased in our patient. A gradual loss of ACTH is a point of concern in some patients with congenital hypopituitarism. Therefore, we suggest careful follow-up monitoring of the hypothalamic-pituitary-adrenal function in patients with 9qSTDS and hypopituitarism as adrenal insufficiency could be lethal, even if ACTH deficiency is not apparent during the first evaluation.
The combination of two relatively rare conditions, 9qSTDS and hypopituitarism, led us to perform WES to obtain additional genetic information for hypopituitarism; however, we were unable to identify any mutations in the known causative genes for hypopituitarism or second hit mutations in genes located in the deleted region. Hypogonadotropic hypogonadism (HH), which results in micropenis and cryptorchidism, in patients with 9qSTDS could be due to a haploinsufficiency of NSMF (MIM # 608137). This gene is located at chr9:140342023-140353786 in the commonly deleted region, encodes a guidance molecule for olfactory axon projections, and plays a role in the neurophilic migration of luteinizing hormone-releasing hormone cells. 5 Several reports have shown that NSMF is associated with normosmic idiopathic HH and Kallmann syndrome (KS), defined by HH and anosmia/hyposmia, either singly or in combination with a mutation in another gene. [6][7][8][9] Recent studies have shown that variants in FGF8, KAL1, and PROKR2, the genes responsible for KS, have been identified in a small number of hypopituitarism. 10,11 Haploinsufficiency of NSMF could partly contribute to pituitary development. Of course, the possibility that hypopituitarism and 9qSTDS are coincident, and that the patient had additional variants in unidentified genes causative for hypopituitarism, cannot be completely excluded.
In conclusion, we present the first case of definite hypopituitarism with a 9q34.3 subtelomeric deletion, thus expanding our understanding of the phenotypic features associated with 9qSTDS. However, hypopituitarism could have been overlooked so far in the patients with 9qSTDS; thus, further investigations or reevaluation of clinical information, especially hormonal evaluations, are warranted to determine whether hypopituitarism is a rare or relatively common presentation in patients with 9qSTDS.