Conradi-Hünermann syndrome

Conradi-Hünermann syndrome is a rare form of chondrodysplasia punctata, a group of genetic disorders of skeletal development in which calcium salts accumulate abnormally in the growing ends of long bones. It is associated with the EBP gene and affects roughly one in 100,000 to one in 200,000 babies. Typical features include mild to moderate growth deficiency, disproportionate shortening of the long bones of the upper arms and thighs, short stature and sometimes curvature of the spine; intellectual disability is rare. The disorder is usually inherited as an X-linked dominant trait and occurs mostly in females, although rare affected males have been reported. Diagnosis is supported by finding elevated sterols in plasma, treatment addresses individual problems such as leg lengthening operations, and most affected females can live a long and normal life. It is also called Happle syndrome, after the physician Rudolf Happle, and carries the names of the German physicians Erich Conradi and Karl Hünermann.