Age/sex: 24-day-old male
Size: 15.3 x 10.4 x 3.4 cm
The specimen consists of a leg from a 24-day-old boy. The shin and thigh bones are shorter than would be expected for the size of the foot. They are also shorter than those of a typical baby of the same age.
Achondroplasia
Although achondroplasia is the most common form of dwarfism (ālittle personā), it is still rare, occurring in only 1 in 25,000 - 30,000 births. It is caused by a mutation in fibroblast growth factor receptor 3 (FGFR3) which results in deficient ossification (formation of bone from cartilage). The condition is autosomal dominant; about 80% of mutations are sporadic, in which case the individualās parents are not similarly affected. Homozygous inheritance is usually fatal, either as stillbirth or shortly after birth as a result of respiratory failure related to an abnormal rib cage.
Most adults measure 4 to 4 Ā½ feet (1.2 to 1.4 meters) in height. Short length affects mainly the arms and legs, the torso being relatively normal. There are also abnormalities of skull structure, which can lead to ear infections, sleep apnea, tooth malocclusion and interference with cerebrospinal fluid drainage that results in hydrocephalus (dilatation of normal cystic spaces within the brain. See Specimen 32). Intelligence is not affected.
Below: Carving of a man with achondroplasia named Djehor on an Egyptian sarcophagus dating from the Late Period (713-332 BCE). Individuals with achondroplasia are well-represented in Egyptian art and burials.
Source: Reeves, C. (1989). Egyptian carving, achondroplasia taken in 1989. Wellcome Collection.
