Comparative skeletal features between Homo floresiensis and patients with primary growth hormone insensitivity (Laron syndrome)

Abstract

Comparison between the skeletal remains of Homo floresiensis and the auxological and roentgenological findings in a large Israeli cohort of patients with Laron Syndrome (LS, primary or classical GH insensitivity or resistance) revealed striking morphological similarities, including extremely small stature and reduced cranial volume. LS is an autosomal recessive disease caused by a molecular defect of the Growth Hormone (GH) receptor or in the post-receptor cascades. Epidemiological studies have shown that LS occurs more often in consanguineous families and isolates, and it has been described in several countries in South East Asia. It is our conclusion that the findings from the island of Flores, which were attributed to a new species of the genus Homo, may in fact represent a local, highly inbred, Homo sapiens population in whom a mutation for the GH receptor had occurred.

Bayesian analysis of a morphological supermatrix sheds light on controversial fossil hominin relationships

“…Henneberg et al are not alone in this. None of the proponents of the pathology hypotheses has identified characters that align the Liang Bua hominins with H. sapiens [63,66,67]. Thus, our results are not particularly surprising.…”

The origin of Homo floresiensis and its relation to evolutionary processes under isolation

“…However, the development of the supraorbital ridges that is seen in patients with Laron syndrome (see Figure 2 in Hershkovitz et al, 2007) is far too small for H. floresiensis. Furthermore, these patients have delicate faces, marked chins, and thin vaults (Obendorf et al, 2008), none of which is the case in H. floresiensis.…”

“…Recently, Hershkovitz et al (2007) explained the small stature and unique anatomical features of H. floresiensis as the result of primary growth hormone insensitivity, known as Laron syndrome. However, the development of the supraorbital ridges that is seen in patients with Laron syndrome (see Figure 2 in Hershkovitz et al, 2007) is far too small for H. floresiensis.…”

“…This hypothesis has not been contradicted by further studies of the cranial (Gordon et al, 2008), postcranial (Tocheri et al, 2007) and endocranial (Falk et al, 2005) anatomy of H. floresiensis. A completely different path to explain the origin of H. floresiensis was followed by other researchers who considered the small hominid from Flores as a modern human, suffering from some kind of pathology or disorder (Henneberg and Thorne, 2004;Weber et al, 2005;Jacob et al, 2006;Martin et al, 2006;Hershkovitz et al, 2007;Obendorf et al, 2008).…”

Descriptions of the upper limb skeleton of Homo floresiensis

“…Nonetheless, alternative interpretations of the LB1 partial skeleton have advocated various modern human developmental syndromes to account for its distinctive morphology. These include claims that the LB1 skeleton manifests characteristics of IGF-1 deficiency or insensitivity (Richards, 2006;Hershkovitz et al, 2007), endemic cretinism (congenital hypothyroidism) (Obendorf et al, 2008), and microcephaly with accompanying developmental abnormalities (Jacob et al, 2006). Although a detailed rebuttal to each of these assertions is beyond the scope of this paper, some claims have been based on inaccurate depictions of H. floresiensis morphology, perhaps due in part to the necessary brevity of the original descriptions of the material.…”