Down Syndrome Diagnosis in LB1

The origin of Homo Floresiensis has been a source of controversy and confusion for physical anthropologists since its discovery was made in 2003. Nicknamed the Hobbit for its small stature, the species has perplexed anthropologists because its features seem too primitive for the time it was living in. This has made it difficult for experts to place H. Floresiensis among our other hominin ancestors. Many theories explaining the species' emergence and attributes have arisen, including one that blames down syndrome for the diminutive stature and primitive features of the hominin's type specimen, LB1. The research article A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis written by Karen L. Baab, Peter Brown , Dean Falk, Joan T. Richtsmeier, Charles F. Hildebolt, Kirk Smith, and William Jungers, explains the invalidity of a down syndrome diagnosis for the Homo Floresiensis type specimen, LB1.

The article's main focus is eliminating the idea that down syndrome is the most likely cause of H. Floresiensis 'undersized characteristics. As the authors note, this claim had persisted among a number of anthropologists who believed the specimen was simply a small modern human that many have been pathologically altered. This includes Robert H. Eckhardt, an anthropologist that most recently wrote an article attempting to dismiss H. Floresiensis as a valid species by supporting a Down Syndrome diagnosis of LB1. Baab et al. utilizes several types of evidence to discount Eckhardt's evaluation of this species, present key differences between LB1 and people with down syndrome, and identify the characteristics of H. Floresiensis that make it a unique species.

Baab et al. attempt to refute the claim of a down syndrome diagnosis with several solid pieces of evidence. This evidence thoroughly highlights the multitude of significant incongruences between LB1 and modern humans with down syndrome. Some of the reasoning that the authors include is that much of a DS diagnosis involves soft tissue qualities, which the fossils found in Liang Bua did not have. The authors also state that, many of the clinical signs of DS are not unique to this syndrome but are present in other syndromes(Baab et al. 3). To support these general statements, Baab et al. also have a plethora of more specified evidence. This includes a table listing the hard tissue features common in those with down syndrome and comparing it to the features of LB1. To expand on that, the authors also feature diagrams comparing neurocranial shape, cranial templates that visually show the difference between LB1 and DS individual, and much more. To further discredit Robert H. Eckhardt and his research, they also included evidence that reject his specific claims. For example, Baab et al. notes that Eckhardt connected LB1 to down syndrome because the type specimen did not have a sphenoid or maxillary sinus. To refute this, the authors include high-resolution medical CT scans showing the presence of maxillary sinuses and suggesting sphenoid sinuses in LB1.

Baab et al. concludes that a diagnosis of down syndrome for LB1 is extremely unlikely because evidence supporting this diagnosis is minimal at best. They believe that LB1 remains a unique species- Homo Floresiensis. I believe that this conclusion is both convincing and logically sound because of the thorough and extensive reasoning provided by the authors. One of their most convincing arguments is the fact that many of the most diagnostic features of down syndrome can simply not be observed in the hard tissue remains of LB1, such as a protruding tongue and single palmar crease. Another would be their acknowledgement that many of the characteristics belonging to modern humans with down syndrome are not unique to this syndrome, making a definitive diagnosis improbable. Although Baab et al. provided much more detailed reasoning than the aforementioned, I found these arguments the most convincing because they made a definitive diagnosis for LB1 seem simply illogical.

In conclusion, I find the research conducted by Baab et al. and presented in A Critical Evaluation of the Down Syndrome Diagnosis for LB1, Type Specimen of Homo floresiensis to be valuable to the field of biological anthropology because it eliminates one reason for the existence of LB1. In my opinion, it is important for anthropologists to be able to determine that Homo Floresiensis is, in fact, a valid and unique species.

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