MON-078 WFS1 Related Disorder in A 4-Month Old Girl

Background: Idiopathic early-onset central diabetes insipidus (CDI) may be due to mutations of arginine vasopressin-neurophysin II (AVP-NPII (AVP)) or wolframin (WFS1/2) genes (1). Clinical Case: A 4-month old girl presented to our pediatric endocrinology clinic due to severe polydipsia-polyphagia and polyuria. Plasma and urine glucose and HbA1c were normal and 24h monitoring of urinary output was elevated (4.2ml/kg/h). We proceeded to a modified 5-h water deprivation test followed by 0.1 mcg DDAVP IM. Results were compatible with partial central DI: at 5-hrs weight loss 5%, urine osmolality 155 from 111 at 0΄and 355 mOsm/kg 2hrs after DDAVP administration. Pituitary MRI was normal with presence of posterior pituitary bright spot and normal pituitary stalk. We initiated therapy with oral desmopressin acetate titrated at the dose of 70mcg x 3/day under close clinical and biochemical surveillance. Hyponatremia, with high natriuresis >100 mmol/L and elevated BNP occurred the 3(rd) day. Fludrocortisone 100 mcg x 2/day controlled natriuresis and supplemental oral NaCl 15% 15ml/day was needed to restore normal electrolytes (2). Marked catch-up growth was observed already at 1 month for height, weight and head circumference. Methods: Whole exome sequencing was performed targeted to a gene panel related to DI, containing AVP gene, WFS1/2 genes and AVPR2/AQP2 genes. Result: Two heterozygous variants were revealed: WFS1:NM_001145853:exon8:c. G997A:p.V333I,WFS1:NM_006005:exon8:c.G997A:p.V333I and WFS1:NM_00114585 3:exon8:c.G1832A:p.R611H,WFS1:NM_006005:exon8:c.G1832A:p.R611H reported as possibly damaging in 1/6 and 4/6 prediction programs respectively. These variants will be checked in both parents to confirm the presumed compound heterozygosity pattern in the child. Conclusion: We present a 4-month old girl with two heterozygous variants of WFS1 gene which may cause early-onset central diabetes insipidus and possibly a WFS1 related disorder (1). Reference: (1) Perrotta S et al. Early-onset central diabetes insipidus is associated with de novo arginine vasopressin-neurophysin II or Wolfram syndrome 1 gene mutations. Eur J Endocrinol. 2015 Apr;172(4):461-72 (2) Papadimitriou DT, Spiteri A, Attilakos A, Papadimitriou A. Cerebral Salt Wasting Complicated by Central Diabetes Insipidus and Growth Hormone Deficiency. Indian J Pediatr. 2018 Jul;85(7):580-581