New research counters claim that the 'Hobbit' had Down syndrome

June 08, 2016

Analysis of a wealth of new data contradicts an earlier claim that LB1, an ~80,000 year old fossil skeleton from the Indonesian island of Flores, had Down syndrome, and further confirms its status as a fossil human species, Homo floresiensis.

From the start, fossils of a tiny population of human-like creatures from Flores (the so-called "Hobbits" of Southeast Asia) have been controversial. Are these remains evidence of a new species of fossil human, Homo floresiensis? Or are these remains simply a population of small-bodied humans (Homo sapiens), like ourselves, but with one or more individuals suffering from a developmental disorder? Researchers recently diagnosed LB1, the most complete individual recovered, with Down syndrome.

New analysis of features from across the skeleton by an international team of researchers led by Karen Baab, Ph.D., Assistant Professor of Anatomy at Midwestern University in Glendale, AZ, convincingly demonstrates that LB1 did not have Down syndrome. In addition to measuring individual bones, the scientists used CT scanning to reconstruct the brain and view internal structures of the skull, as well as assessing the 3-dimensional (3D) shape of the skull.

The study, titled "A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis," is published in the June 8, 2016 edition of PLOS ONE.

Down Syndrome

The diagnosis of Down syndrome is the most recent in a long line of diseases attributed to this particular skeleton. Down syndrome is a chromosomal disorder characterized by cognitive delays and often certain physical features, including reduced stature and brain size. The original diagnosis also emphasized the wide and short (front-to-back) shape of the skull, shape of the chin, and short femur (thigh bone) in LB1 as evidence of Down syndrome. Diagnosing Down syndrome in fossils is complicated by the fact that many common features are found in the soft tissues of the body, which do not fossilize. Nevertheless, this study provides new information about the size and shape of the brain and skull in the Down syndrome population.

Down Syndrome Diagnosis a Bust

For the current study, the team compared physical traits preserved in the skeleton of LB1 to those found in Down syndrome. While people with Down syndrome are not identical to one another, it was nevertheless clear that LB1 was very distinct from all humans, including those with Down syndrome.

The study found that LB1's brain was much smaller than that seen in Down syndrome individuals. Likewise, the shape of the skull vault, which surrounds the brain, and chin anatomy were both outside the range seen in humans, with or without Down syndrome. Moreover, the diminutive LB1 individual, estimated to be just over a meter (1.09 m) in height (or 3' 7"), was well below the height range of comparable individuals with Down syndrome. In fact, females with Down syndrome from Turkey reach a comparable height as the adult LB1 by 6.5 years of age and are considerably taller as adults (1.45 m or 4' 9" on average). The femur is disproportionately short in LB1 relative to the feet and arms compared to all humans, regardless of whether they have Down syndrome.

LB1 Remains Type Specimen of Homo Floresiensis

Importantly, this study indicated that LB1 not only differed from individuals with Down syndrome, but was more clearly aligned with more archaic human species. Its small brain, low cranial vault shape, absence of a chin, smaller body size and limb proportions all point to a pre-Homo sapiens ancestry. The authors conclude: "The skeletal evidence overwhelmingly contradicts a diagnosis of Down syndrome. Rather, our study is yet further evidence that Homo floresiensis was a distinct species with a fascinating, if somewhat nebulous, evolutionary history."
Journal Reference:

Karen L. Baab, Peter Brown, Dean Falk, Joan T. Richtsmeier, Charles F. Hildebolt, Kirk Smith, William Jungers. (2016) A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis. PLOS ONE.

Midwestern University is a graduate degree-granting institution specializing in the health sciences with eleven colleges and two campuses. The Illinois campus, located on a 105-acre site in Downers Grove, is home to over 2,900 students and five colleges: the Chicago College of Osteopathic Medicine, the Chicago College of Pharmacy, the College of Health Sciences, the College of Dental Medicine-Illinois, and the Chicago College of Optometry. The Arizona campus, located on a 156-acre site in Glendale, is home to over 3,300 students and six colleges: the Arizona College of Osteopathic Medicine, the College of Pharmacy-Glendale, the College of Health Sciences, the College of Dental Medicine-Arizona, the Arizona College of Optometry, and the College of Veterinary Medicine. The University is accredited by The Higher Learning Commission, a Commission of the North Central Association of Colleges and Schools. For more information, visit or call 623.572.3215.

Midwestern University

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to