De novo HNF1 homeobox B mutation as a cause for chronic, treatment-resistant hypomagnesaemia.
Endocrinol Diabetes Metab Case Rep
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29-year-old female presenting with an 8-year history of unexplained hypomagnesaemia, which was severe enough to warrant intermittent inpatient admission for intravenous magnesium. Urinary magnesium was inappropriately normal in the context of hypomagnesaemia indicating magnesium wasting. Ultrasound imaging demonstrated unilateral renal cysts and computed tomography of kidneys, ureters and bladder showed a bicornuate uterus. Referral to genetic services and subsequent testing revealed ade novo HNF1Bdeletion. Learning points: HNF1B loss-of-function mutations are one of the most common monogenic causes of congenital anomalies of the kidney and urinary tract.Those withHNF1Bmutations may have some of a constellation of features (renal and hepatic cysts, deranged liver function tests, maturity onset diabetes of the young type 5 (MODY5), bicornuate uterus, hyperparathyroidism, hyperuricaemic gout, but presenting features are highly heterogeneous amongst patients and no genotype/phenotype correlation exists.HNF1Bmutations are inherited in an autosomal dominant pattern but up to 50% of cases arede novo.HNF1Bmutations can be part of the Chr17q12 deletion syndrome, a contiguous gene deletion syndrome.Inorganic oral magnesium replacements are generally poorly tolerated with side effects of diarrhoea. Organic magnesium compounds, such as magnesium aspartate, are better absorbed oral replacement therapies.
AuthorsStiles, CE; Thuraisingham, R; Bockenhauer, D; Platts, L; Kumar, AV; Korbonits, M
- Endocrinology