Height, sitting height and leg length in patients with hypophosphataemic rickets

Height, sitting height (SH) and subischeal leg length (SLL) were determined in 5 boys and 11 girls with hypophosphataemic (vitamin D-resistant) rickets, aged 4-14 years. Their average height was -2.05 +/- 1.22 SDS, and SLL (average value: -2.59 +/- 1.18 SDS) was more reduced than SH (average value: -0.91 +/- 1.37 SDS). SLL and SH were abnormally low in 11 and 3 of the patients respectively. The difference between SLL and SH was abnormally low in only 4 of the children, indicating a mild degree of disproportion. None of the patients had relatively long legs. There was no relation between height and the degree of disproportion, a finding which tallied with the relatively mild degree of disproportion. This indicated that the normal interindividual differences in proportion were more important than a preferential effect of rickets on leg length.