Hypomagnesemia-hypercalciuria-nephrocalcinosis and ocular findings: a new claudin-19 mutation.
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive syndrome that affects the tight junction proteins claudin-16 and claudin-19 in the thick ascending limb. In patients with claudin-19 mutations, additional symptoms such as visual impairment and other ophthalmologic findings are expected. In this report, we present a seven-year-old girl with polyuria and polydipsia. She was the daughter of consanguineous parents with a history of neonatal hypomagnesemic convulsion. On physical examination, bilateral horizontal nystagmus, retinitis pigmentosa and severe myopia were detected. Laboratory examination revealed hypomagnesemia, hypercalciuria and hypermagnesuria. A clinical diagnosis of FHHNC caused possibly by claudin-19 mutation was decided with the ocular findings. DNA analysis revealed a novel homozygous nonsense mutation (W169X) in the CLDN19 gene. In conclusion, in a patient with consanguineous parents, history of hypomagnesemic convulsion and disturbed organization and development of the retina, a diagnosis of FHHNC caused by claudin-19 mutation should be considered.
Division of Pediatric Nephrology, Department of Pediatrics, Kocaeli University Faculty of Medicine, Kocaeli, Turkey.
Zelal
Z
Ekinci
Levent
L
Karabaş
Martin
M
Konrad
D002648:Child; D057167:Claudins / Q000235:genetics*; D018389:Codon, Nonsense; D003241:Consanguinity; D005260:Female; D006720:Homozygote; D006801:Humans; D053565:Hypercalciuria / Q000235:genetics*; D008275:Magnesium Deficiency / Q000235:genetics*; D009216:Myopia / Q000235:genetics; D009397:Nephrocalcinosis / Q000235:genetics*; D009759:Nystagmus, Pathologic / Q000235:genetics; D012174:Retinitis Pigmentosa / Q000235:genetics
C508912:CLDN19 protein, human; D057167:Claudins; D018389:Codon, Nonsense