Biology Reference
In-Depth Information
cretinism
Cretinism is a condition of stunted growth and mental retardation that
result from a deficiency of thyroid hormone, which can occur for a vari-
ety of reasons, including a diet that lacks enough iodine. Infants of moth-
ers deficient in iodine are likely to be born with the condition. Children
with cretinism have broad faces with flat noses. If untreated, they become
smaller for their age as they grow up, which results in dwarfed adults.
The condition can also develop in adults as a reaction to an underfunc-
tioning thyroid gland (or its removal), which may be associated with an
enlarged pituitary gland and, again, environmental factors such as too
little iodine in the diet. The adult condition is called myxedematous
cretinism (ME). Peter Obendorf, of the Royal Melbourne Institute of
Technology, in Australia, and his colleagues suggested that LB1 and the
other hobbits were individuals with ME rather than a previously unrec-
ognized species of Homo . 67
The cretinism hypothesis is based on statistical analyses of various
measurements from the skeletons of normal individuals, cretins, a few
fossil hominins, and LB1. To its credit, this study rejected both micro-
cephaly and Laron syndrome as explanations for LB1. It did not, how-
ever, make a convincing case that LB1 or, by extension, the other hobbits
were cretins. One reason for this is that traits for LB1 were repeatedly
scored as resembling those of cretins, when, in fact, they did not. 68 For
example, LB1 was claimed to have had an enlarged pituitary gland on
the basis of measurements taken from a published image of the bottom
of LB1's skull. However, the image (which came from one of my team's
papers) failed to reveal the dimensions of the bony hollow that contains
the pituitary gland, because the area in question had been damaged . 69
Furthermore, inspection of the 3D-CT data from near this region of
LB1's skull strongly suggests that the hollow for the pituitary was not
enlarged.
Similarly, LB1 was erroneously scored as having other traits in com-
mon with cretins, such as an opening between the bones of the top
part of the skull (the anterior fontanelle), an absent frontal sinus, and
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