The "Hobbit" skeleton was found in 2003 along side some other fun archaeological stuff. The skeleton is almost complete, and was originally determined to be a new species of primitive human. Named Homo floresiensis, this new species has been called "the most extreme human ever discovered" and was classified as a new species based on some significant differences seen between it and Homo sapiens.
Some researchers who were reexamining the Homo floresiensis skeleton came to a controversial conclusion; instead of being a new species, the "Hobbit" skeleton looks like it might have simply been a human with Down syndrome. Bianca Nogrady from ABC Science Online writes, the Hobbit skeleton was of a "a one-metre-tall adult figure with a small skull, asymmetrical features, shortened upper leg bones, and large flat feet." Measurements of the skeleton's height, limb, torso, and skull also closely resemble those Homo sapiens with Down syndrome, strengthening the conclusion.
The research team also found the Hobbit might have had had hypothyroidism, though the skeleton doesn't exhibit all of the physical symptoms you would normally expect. Hypothyroidism is a disorder of the thyroid gland and, long story short, it basically doesn't produce enough of the thyroid hormone and causes all sorts of unpleasant things such as delayed physical and mental development in children.
The research has come under some fire from the anthropology community. Colin Groves, a bioanthropologist at the Australian National University, calls the research "implausible" and has some serious bones to pick with the methodology. For example, he states, "The main paper makes a lot of the femur being abnormally short and they never actually show that it is abnormally short" and then he shows the femur is more proportional with different specimens from the same era. Groves also complains that some of the asymmetry could have been the result of excavation instead of by genetic causes.
Naturally, one of the authors of the paper responded to the accusations made by Groves, and the cycle continues. Was the Homo floresiensis really just a Homo sapien with Down syndrome? Maybe. Anthropologists will continue to debate the paper's findings and the rest will be history.