[MIM 248 250]

(HOMG3, renal hypomagnesemia type 3, FHHNC without ocular involvement)

Rare. Autosomal recessive transmission of a  mutation of the CLDN16 gene on 3q28-q29 that codes for the CLAUDIN16 protein or paracelline-1, which is involved in the formation of intercellular tight junctions and is thus involved in the reabsorption of Ca and Mg at the level of dilated section of the ascending loop of Henle. Hypomagnesemia and hypercalciuria which arise locally are responsible for the development of nephrocalcinosis, the formation of urolithiasis and a progressive renal insufficiency (which becomes terminal between the age of 20 and 30 years).

Also: hyperuricemia, and secondary hyperparathyroidism (> 80%), partial distal tubular acidosis, polyuria.

Ocular anomalies are observed in 30-50% of the cases: myopia, horizontal nystagmus, corneal lithiasis, sometimes chorioretinitis.

Treatment: Mg supplements and thiazide diuretics.

Anesthetic implications: 

check renal function and electrolytes; eye protection

References : 

• Sikora P, Zajaczkowska M, Raganowicz T et al. 
  Bilateral slipped capital femoral epiphysis  in a male adolescent with familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC), chronic renal failure, and severe hyperparathyroidism. 
  Eur J Pediatr 2014; 173: 247-9.

Updated: March 2019