Los niños del Cauca. I. Descripción de un foco de raquitismo dependiente de la vitamina D, Tipo II.

Abstract

A large group of patients with low extremity deformities (genu varurn, genu valgun or both) was detected in the northern area of the Cauca department. Those deformities resembled a rickets picture, both clinically and radiolocically. Most of them carne from a semi-isolated population group of Afro-mestizo ancestry, located in La Toma county, Suárez municipality. Comparative biochemical studies between 64 patients and 109 sane subjects (first degree relatives) showed as light hypocalcemia, increased sericphosphorus levels, amarkedly high alkaline phosphatase titers, normal protein and albumin values,and high parathormone serictiters. Twenty four hour urinalysis showed hypocalciuria and hypophosphaturia. 25(OH)D,and 1a,25(OH),D3 seric titers were determined to establish rickets type. There was a marked increase of 1, 25 (OH) D, allowing us to conclude that it corresponded to vitamin D-dependet-rickets, type II.Thelatter is an autosomal recessive genetically transmitted rickets with clinical and laboratory manifestations due to a defect in the vitaminD receptor. One hundred and fifteen patiens started therapy with 1u. 25 (OH). D, (0.50 ug/d), calcium (1,840 mg/d), phosphorus (1,424 mg/d) given in two doses per day. Serum titers of 21 patients were analysed before and after treatment, and values tended to become normal. Molecular studies, mRNA and cDNA vitamin D receptor gen, obtained from fibroblast cultures from two patients with severe compromise, showed a normal nucleotide sequence. A comparison between clinical and laboratory findings of the 20 reported cases in the literature and our 64 cases was done; we emphasize our observations, including the early onset of the clinical picture, pain or muscular weakness absence, without baldness, normal phosphorus values and a slight secundary hyperparathy roidism, which indicates the great heterogeneity of this particular type of rickets.