Hypophosphataemic rickets

X-Linked hypophosphataemic rickets (XLH) is frequently associated with short stature even when conventional treatment (1, 25-dihydroxyvitamin D(3) or 1alpha-hydroxyvitamin D(3) plus inorganic phosphate salts) is administered for a long time. The pathogenesis of growth retardation is probably multifactorial. Affected patients usually show normal growth hormone (GH) secretion. In some poorly growing XLH patients, long-term GH treatment associated with conventional therapy improves linear growth. GH treatment also increases phosphate retention but this effect is transient.     

Vitamin-D-dependent rickets type 2

Vitamin-D-dependent rickets type 2 results from autosomal recessive mutations of the vitamin D receptor gene. With congenital total body alopecia and onset of rickets during the second half of the first year of life, patients display rapidly progressing rachitic bone changes, hypocalcemia and secondary hyperparathyroidism. This article describes extensive personal experience with about one third of the world's reported cases, their clinical course, the physiological consequences, diagnostic steps, molecular findings and therapeutic approach, as they developed over the course of the last 25 years.     

Three DNA markers for hypophosphataemic rickets

Summary This paper presents three markers, 16D/E, pHMAI (DXS208), and CRI-L1391 (DXS274), that show close linkage for X-linked hypophosphataemic rickets (HYP). DXS274 is closely linked to HYP ( _max= 0.00, Z_max = 4.20), and DXS41 (99.6), ( _max= 0.00, Z_max = 5.20). Marker 16D/E maps distal to the disease locus ( _max= 0.05, Z_max = 3.11). The pHMAI probe recognises the same restriction fragment length polymorphism (RFLP) as 99.6. Multipoint analysis suggests that the most probable order of loci is Xpter-(DXS43, 16D/E)-HYP-DXS274-(DXS208, DXS41)-Xcen. The location of DXS274 distal to HYP cannot be excluded, as no recombinants were observed between DXS274 and HYP, or between DXS274 and DXS41/DXS208. One of the families contains a large number of recombinants, four of which are double recombinants. This most probably means that the disease in this family maps elsewhere on the X chromosome or on an autosome, indicating locus heterogeneity.     

Screening Rastafarian children for nutritional rickets.

We examined 42 Rastafarian children under 5 years of age who were registered with a single inner city general practice to determine the prevalence of nutritional rickets. Twenty children were receiving a strict vegan(I-tal) diet and were considered to be at high risk of developing rickets and were referred for biochemical and radiological investigation. Seven of 20 children investigated had rickets, giving an overall prevalence of 7/42. Treatment with oral cholecalciferol was successful in all seven children. Fourteen out of 18 children had evidence of iron deficiency, with low haemoglobin concentrations and hypochromic-microcytic blood films. Before this study Rastafarian children rarely attended the well baby clinic, received no vitamin supplements, and few had been immunised. They now regularly attend the clinic, receive vitamin and iron supplements, and all have completed primary immunisation.