Abstract

NEGRI, Armando Luis; NEGROTTI, Teresa; ALONSO, Guillermo  and  PASQUALINI, Titania. Different forms of clinical presentation of an autosomal dominant hypophosphatemic rickets caused by a FGF 23 mutation in one family. Medicina (B. Aires) [online]. 2004, vol.64, n.2, pp.103-106. ISSN 0025-7680.

In this report we describe different forms of clinical presentation of an autosomal dominant hypophosphatemic rickets (ADHR) in 4 members of the same family as well as the treatment used in these patients and their response to it. Patient N° 1: a 60 year old female who consulted for bone pain. Bone densitometry showed osteoporosis. Laboratory assays showed hypophosphatemia with low renal phosphate threshold, high total alkaline phosphatase, normal intact PTH and normal serum calcium. With neutral phosphate and calcitriol, the biochemical parameters normalized and bone densitometry improved significantly in less than a year. Patient N° 2: her grand daughter consulted at 1 year and  8 months of age for growth retardation (height at percentile 3) and genu varum. Laboratory assays showed low serum phosphate and high total alkaline phosphatase; thickening and irregular epiphyseal borders of the wrists were observed radiologically. She began treatment with calcitriol and phosphorus with normalization of laboratory parameters and  increase in growth (height increasing to percentile 50 after 20 months of therapy). Patient N° 3: mother of patient N° 2, she had no clinical manifestations and normal densitometry but presented low serum phosphate (1.9 mg/dl) that normalized with neutral phosphate therapy. Patient N° 4: he was the youngest son of  Patient N° 1, who had had hypophosphatemic rickets, by age 5; his serum phosphate normalized without treatment. At age 29, he presented normal serum phosphate and bone densitometry. Genomic DNA analysis performed in patient N° 3, showed missense mutation with substitution of arginine at position 179 for glutamine. The family was catalogued as having autosomal dominant hypophosphatemic rickets/osteomalacia.

Keywords : Autosomal dominant hypophosphatemic rickets; Fibroblast growth factor 23; Renal phosphate wasting; Hereditary hypophosphatemic rickets.

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