Hereditary hypophosphatemic rickets with hypercalciuria (HHRH) is a new autosomal form of
hypophosphatemic rickets, recently described. This disease is characterized, and differs from other forms of
hereditary hypophosphatemic rickets and/or
osteomalacia by increased serum levels of
1,25-dihydroxyvitamin D,
hypercalciuria and complete remission of the disease on
phosphate therapy alone. However, only another probable Israeli kindred, and seemingly a few sporadic cases from Europe, North America and Japan have been reported in the literature. We describe here a new kindred of Jewish Yemenite origin (unrelated to other Israeli families) with typical HHRH. Two additional members of this family suffer from a milder asymptomatic form of the disease, which presents as absorptive
hypercalciuria without signs or symptoms of
bone disease. It seems to us that HHRH is underdiagnosed, due to its similarity to other hypophosphatemic syndromes in clinical, radiological and most biochemical parameters. Therefore, it is recommended that urinary
calcium excretion and serum
1,25-dihydroxyvitamin D concentrations be measured in every patient with
hypophosphatemic rickets/and or
osteomalacia before the initiation of any
therapy. The correct diagnosis of HHRN is of immense therapeutic implications.
Phosphate therapy alone could cause a complete remission in HHRH, while the addition of active
vitamin D metabolites, as is recommended in
hypophosphatemic vitamin D resistant rickets, could cause deterioration in the patient's condition.