Abstract
BACKGROUND: Pituitary stalk interruption syndrome (PSIS) is a rare entity characterized by thin or absent pituitary stalk, hypoplastic/aplastic anterior pituitary and ectopic posterior pituitary (EPP) on magnetic resonance imaging (MRI). PSIS can be associated with variable degrees of pituitary insufficiency 1. Most cases of combined pituitary hormone deficiency are sporadic, however in familial cases, there can be AD or AR inheritance with more than 30 genes identified in association with combined pituitary hormone deficiency (CPHD). We describe how diagnosis of 2 children with PSIS led to the discovery of the condition in their mother.
Clinical Case: Child 1 presented at age 3yrs with growth failure in 2003 with ht z score -4.24 SD. Subsequent work up revealed low IGF-1 (< 25 ng /mL) and MRI showed EPP, small anterior pituitary gland and absent pituitary stalk. No GH stim test was performed. He was started on GH supplementation and later was diagnosed with central hypothyroidism, central adrenal insufficiency and hypogonadotropic hypogonadism and is doing well on multiple hormone replacement at age 19 yrs.
Child 2, a half-brother to child 1 (same mother), presented at age 1yr with growth failure in 2017 with ht z score -2.06. GH stimulation test with glucagon was abnormal and resulted in a very low GH response (peak GH 0.52 ng/mL). MRI showed EPP with small anterior pituitary gland and interruption of the stalk. Later he was found to have central hypothyroidism and mild central adrenal insufficiency. He is receiving standard hormone replacement at 3 yrs of age.
Mother of above 2 patients presented 6 mos postpartum in 2017 after her 7th and last pregnancy with fatigue and amenorrhea. Laboratory evaluation revealed central hypothyroidism (FT4 0.76 ng/dL) and she was prescribed levothyroxine followed by resumption of her menses. She was unable to breastfeed her children due to lack of supply. There were no concerns for DI, amenorrhea or infertility. She was referred to Endocrinology in 2019 for persistent fatigue with a question of GH deficiency. IGF-1 level was normal 114 ng/mL(z score -0.39) and GH stimulation test (clonidine + glucagon) was abnormal with peak GH 1.85 ng/ml. MRI showed EPP with hypoplastic pituitary stalk. Genetic testing was done for CPHD Sequencing Panel at Prevention Genetics which includes GL12, HESX1, LHX3, LHX4, OTX2, POU1F1, PROP1F1, PROP1, SOX2, SOX3 genes and results were negative. She has 4 other children (21, 12, 11, 10yrs) who are currently being investigated for hormone deficiencies. One child died at 3 months of age due to SIDS.
Conclusion: We present 3 family members with PSIS. This family highlights the variable clinical phenotype of PSIS and importance of careful family history when evaluating children with congenital pituitary abnormalities and supports the need for more extensive gene panels for evaluation of CPHD.
Reference:. Acta Endocrinologica, 2017. 13(1):96–105
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