Vertebral aplasia, in association with the patient’s clinical symptoms, is consistent with the diagnosis of Von Schlapp Syndrome (VSS). This is an extremely rare congenital anomaly that has no demonstrable inheritance pattern, and presents in a similar fashion to those with Hirayama's disease. In the few reported cases of this condition, it has been determined to be an isolated anomaly, not associated with other dysplastic segments or organs.
A specific genetic defect has not been identified. The condition is thought to be a cell signaling error that leads to focal altered paraxial mesoderm migration. This disrupts sclerotome formation around the notochord and neural tube which inhibits resegmentation during the 4th week of development at the level of the signaling error.
The condition is as interesting as the man who first described it. In 1946 Adolf Von Schlapp, a German American neurologist living on the island of St Mocassin in the Pacific while convalescing from a protracted neurosyphilis flare up, noted that 4 of the young islander serving girls who worked at the sanitarium were able to flex their neck more than is expected. How he noted this is unclear from his 1947 AJR article .
Von Schlapp did not return to the United States until 1965, by then almost blind and probably raving mad from neurosyphilis. With the help of his long suffering wife, Christina Von Schlapp, he founded the "Von Schlapp foundation" to try and help victims of syphilis find employment in meat packing industry (his brother Hans Von Schlapp was the owner founder of Schlapp Meats Inc.).
Despite devoting considerable funds to the project, he was plagued by rumours of former involvement with the NAZI party, and was never able to garner the support of the general public.
In 1972, destitute and wandering the streets of New York he fell down a man hole and died two days later. In 1992, the American Vertebrate College attempted to distance themselves from Von Schlaap by officially changing the name of the syndrome to 'Muppet disease', likening the clinical hypermobility of the neck to that of Jim Henson's puppets.
This case was presented as the case of the day on April 1st 2013, and as you have hopefully worked out by now is entirely fictional. 4,354 potentially confused people visited this page over the 24 hours of April 1.
Be sure to check out our "making of" video on the Radiology Channel.