Vitamin D-dependent rickets type II in a cat.

A cat with clinical signs Indicating rickets was diagnosed as having a defect of vitamin D receptors. Clinical signs had been seen from four months of age. Treatment with calcium supplementation and various forms of vitamin D did not alter plasma calcium levels or reverse skeletal lesions of lateral antebrachial bowing, lumbar spinal lordosis and costochondral beading. Analgesics were effective for relieving skeletal pain during the bone growth phase and were withdrawn when the animal reached skeletal maturity. Therapy for hip osteoarthritis was given from five years of age until the cat was euthanased at nine years of age as a result of refractory hip pain.

Evaluation of vitamin D status of llamas and alpacas with hypophosphatemic rickets.

OBJECTIVE: To evaluate vitamin D concentrations in juvenile llamas and alpacas with hypophosphatemic rickets. DESIGN: Prospective cohort study. ANIMALS: 21 llamas (14 with rickets, 7 clinically normal) and 9 alpacas (6 with rickets, 3 clinically normal). PROCEDURES: Blood samples were collected at the time of diagnosis and prior to the initiation of treatment. Serum concentrations of calcium, inorganic phosphorus, and 25-hydroxycholecalciferol (vitamin D3) were determined on all samples. Comparisons were completed for disease status, age, sex, species, month of birth, and all interactions. RESULTS: Serum concentrations of phosphorus and vitamin D were lower in affected llamas and alpacas than in clinically normal llamas and alpacas, even when mean concentrations were adjusted for age differences. Species (llama or alpaca), sex, and age did not affect any of the metabolite concentrations within this study population. Month of birth influenced vitamin D concentrations and number of affected llamas and alpacas per month. The greatest number of affected llamas and alpacas was identified between January through March, suggesting a seasonal pattern to this syndrome. Treatment of affected llamas and alpacas with vitamin D resulted in increased concentrations of phosphorus and vitamin D. Serum phosphorus concentration was best predicted by 2 independent variables (serum vitamin D concentration and month of birth). CLINICAL IMPLICATIONS: We believe vitamin D deficiency is the primary cause of hypophosphatemic-rickets of growing camelids, and the observed hypophosphatemia is secondary to a primary deficiency of vitamin D. Appropriate treatment with vitamin D supplements can correct hypophosphatemia and vitamin D deficiency in camelids.

Severe hypophosphatemia associated with diabetes mellitus in six dogs and one cat.

Severe hypophosphatemia was found in 6 diabetic dogs and in one diabetic cat. The cat suffered from hemolysis, and one dog had seizures, both apparently as a result of the severe hypophosphatemia. Clinical signs were not determined solely by the serum concentration of phosphorus, as seen in 5 other patients that did not have signs of disease despite similar serum phosphorus concentrations.

The Gy mutation: another cause of X-linked hypophosphatemia in mouse.

An X-linked dominant mutation (gyro, gene symbol Gy) in the laboratory mouse causes hypophosphatemia, rickets/osteomalacia, circling behavior, inner ear abnormalities, and sterility in males and a milder phenotype in females. Gy maps closely (crossover value 0.4-0.8%) to another X-linked gene (Hyp) that also causes hypophosphatemia in the mouse. Gy and Hyp genes have similar quantitative expression in serum phosphorus values, renal excretion of phosphate, and impairment of Na+/phosphate cotransport by renal brush-border membrane vesicles. These findings indicate that independent translation products of two X-linked genes serve phosphate transport in mouse kidney and thereby control phosphate content of extracellular fluid. The Gy translation product, unlike the Hyp product, is also expressed in the inner ear. These findings have implications for our understanding of the human counterpart known as "X-linked hypophosphatemia."

Abnormal trace mineral metabolism in adult X-linked hypophosphatemic mice: a possible role of increased food intake.

X-linked hypophosphatemia is a human and mouse disease characterized by reduced renal tubular reabsorption of phosphate, hypophosphatemia, and dwarfism. The gene is X-linked and dominant. There have been conflicting reports in the literature regarding possible malabsorption of minerals by the intestine as well. In this study we examined the mineral status in adult X-linked hypophosphatemic (Hyp) mice by measuring trace minerals in blood, bone, muscle, liver and hair and by performing a balance study for Ca, P, Mg, Na and K. The results indicate that Hyp mice have higher than normal levels of plasma iron, bone manganese and zinc, liver iron, and muscle zinc. The trace minerals in hair were not significantly affected. The balance study showed that the content of Ca, P, Mg, Na and K of the urine and feces of normal and Hyp mice were nonsignificantly different. Hyp mice did consume more diet per gram body weight. We conclude that there is no deficiency in intestinal mineral absorption in adult Hyp mice. No tissues studied were found to have reduced trace mineral levels. In fact, where differences occurred, Hyp mice had elevated trace mineral levels in various tissues and blood. This was probably the result of the increased dietary intake per gram body weight in the Hyp mice.