ABSTRACT
Presentamos el caso clínico de un varón de 50 años de edad que consulta por presentar una enfermedad renal litiásica recidivante y una nefrocalcinosis. En la exploración clínica destacó una talla baja y un genu varo bilateral importante. Entre los datos bioquímicos se apreciaba una pérdida renal de fosfatos intensa con hipofosfatemia, una 25 OH vitamina D3 normal, una 1,25 OH2 vitamina D3 elevada y una hipercalciuria. La hormona paratiroidea (PTHi) se encontraba disminuida y en la ecografía renal se confirmó la existencia de una nefrocalcinosis bilateral grave, localizada en la médula renal. Además, se constató una insuficiencia renal crónica incipiente y una acidosis tubular renal incompleta, ambas secundarias a la nefrocalcinosis y no directamente relacionadas con la enfermedad basal. En el estudio molecular se encontró un cambio en homocigosis en el intrón 5 del gen SLC34A3 (NM_080877.2:c[448+5G>A]+[448+ 5G>A]). Sus tres hijos eran portadores de esta misma variante en heterocigosis y, aunque clínicamente estaban asintomáticos, dos de ellos tenían una hipercalciuria. Todos estos datos parecían (..) (AU)
We report a case of a male aged 50 years who consulted for renal disease recurrent lithiasis and nephrocalcinosis. The clinical examination showed external signs of rickets/osteomalacia and biochemical data as well as a severe loss of renal phosphate with hypophosphatemia, normal 25 OH vitamin D, high 1,25 OH vitamin D and hypercalciuria. Parathyroid hormone was low and renal ultrasound confirmed the existence of severe bilateral medullary nephrocalcinosis. They also found incipient chronic renal failure and incomplete renal tubular acidosis, both secondary to nephrocalcinosis and unrelated to the underlying disease. The molecular study found a change in homozygosity in intron 5 of gene SLC34A3 (NM_080877.2:c[ 448 +5G>A] + [ 448 +5G>A] ). His three children were carriers of the same variant in heterozygosis and although they were clinically asymptomatic two of them had hypercalciuria. All these data suggest that the patient had hereditary hypophosphataemic rickets with hypercalciuria (HHRH) secondary to an alteration in the sodium dependent phosphate cotransporter located in proximal tubule (NaPi-IIc). The HHRH is transmitted by autosomal recessive inheritance and is an extremely rare form of hypophosphatemic rickets. The diagnosis and treatment are essential to prevent bone sequelae of rickets and nephrocalcinosis. A correct differential diagnosis with other forms of hypophosphatemic rickets has implications on the treatment, as the management based only on phosphorus supplementation usually corrects all clinical and biochemical abnormalities, except for the loss of phosphorus in the urine. The exogenous supply of calcitriol, as advised in other hypophosphatemic rickets, may induce renal calcium deposits and nephrocalcinosis and worsens the prognosis (AU)
Subject(s)
Humans , Male , Middle Aged , Familial Hypophosphatemic Rickets/diagnosis , Hypercalciuria/diagnosis , Nephrocalcinosis/prevention & control , Calcitriol/therapeutic useABSTRACT
We report a case of a male aged 50 years who consulted for renal disease recurrent lithiasis and nephrocalcinosis. The clinical examination showed external signs of rickets/osteomalacia and biochemical data as well as a severe loss of renal phosphate with hypophosphatemia, normal 25 OH vitamin D, high 1,25 OH vitamin D and hypercalciuria. Parathyroid hormone was low and renal ultrasound confirmed the existence of severe bilateral medullary nephrocalcinosis. They also found incipient chronic renal failure and incomplete renal tubular acidosis, both secondary to nephrocalcinosis and unrelated to the underlying disease. The molecular study found a change in homozygosity in intron 5 of gene SLC34A3 (NM_080877.2:c[ 448 +5G>A] + [ 448 +5G>A] ). His three children were carriers of the same variant in heterozygosis and although they were clinically asymptomatic two of them had hypercalciuria. All these data suggest that the patient had hereditary hypophosphataemic rickets with hypercalciuria (HHRH) secondary to an alteration in the sodium dependent phosphate cotransporter located in proximal tubule (NaPi-IIc). The HHRH is transmitted by autosomal recessive inheritance and is an extremely rare form of hypophosphatemic rickets. The diagnosis and treatment are essential to prevent bone sequelae of rickets and nephrocalcinosis. A correct differential diagnosis with other forms of hypophosphatemic rickets has implications on the treatment, as the management based only on phosphorus supplementation usually corrects all clinical and biochemical abnormalities, except for the loss of phosphorus in the urine. The exogenous supply of calcitriol, as advised in other hypophosphatemic rickets, may induce renal calcium deposits and nephrocalcinosis and worsens the prognosis.
