Schimke-immuno-osseous dysplasia is a rare autosomal-recessive multisystem 
disorder with the main clinical features of disproportionate growth deficiency, 
defective cellular immunity, and progressive renal disease. It is caused by 
mutations of SMARCAL1, a gene encoding a putative chromatin remodeling protein 
of unknown function. Because a detailed description of the clinical features is 
an essential first step in elucidating the function of SMARCAL1, we present the 
first detailed anthropometric data for Schimke-immuno-osseous dysplasia 
patients. By comprehensive anthropometric examination (28 parameters) of 8 
patients (3 females) with the typical findings of Schimke-immuno-osseous 
dysplasia (mean age: 14.8 years; range: 4.9-30.5 years) and 304 patients (117 
females) with congenital and hereditary chronic kidney disease (mean age: 10.7 
+/- 4.8 years; range: 3-21.8 years), we show that Schimke-immuno-osseous 
dysplasia patients differ significantly from those with other forms of chronic 
kidney disease. z scores were calculated with reference limits derived from 5155 
healthy children (2591 females) aged 3 to 18 years. The key finding was that, in 
the latter group, median leg length was significantly more reduced than sitting 
height, whereas in Schimke-immuno-osseous dysplasia patients, the reduction of 
sitting height was significantly more pronounced than for leg length. Therefore, 
the ratio of sitting height/leg length might be a simple tool for the clinician 
to distinguish Schimke-immuno-osseous dysplasia from other chronic kidney 
disease patients. Schimke-immuno-osseous dysplasia is very likely if this ratio 
is < 0.83. However, other forms of chronic kidney disease have to be discussed 
in case of a ratio > 1.01.