Category Archives: Palaeopathology

Heritage Of A Deadly Disease Pinpointed With Help From Iceland’s Genealogical Database

A collaboration of scientists from Iceland and the United States has used Iceland’s genealogical database* to trace the ancestors of patients suffering from hereditary cystatin C amyloid angiopathy (HCCAA). Analysis shows that the deadly mutation in the cystatin C gene, L68Q, derives from a common ancestor born roughly 18 generations ago, around 1550AD.

This dominantly inherited disease, which is due to a mutation in cystatin C (L68Q), strikes young adults with healthy blood pressure. The disease results in death from repeated brain haemorrhages, on average by the age of 30. The origin of the mutation causing HCCAA was previously unknown, but using DNA haplotype analysis* the scientists have shed light on the history of this autosomal dominant disease that has high penetrance in contemporary Icelanders.

The scientists found that 200 years ago, obligate carriers of the mutation lived a normal life span compared to the control population (their spouses). In carriers born around 1820, however, a trend of shortening life span began, resulting in an average life span of only 30 years in people born around 1900. This 30-year lifespan has stayed constant since then in both men and women.

At the same time, a matrilinear effect appeared whereby those who inherited the mutation from the mother died earlier. For carriers born after 1900, the difference is a loss of 9.4 years for those who inherited the mutation from their mothers rather than their fathers. Based on this information, the authors propose that the traditional diet of the nation (which in the past consisted largely of whey-preserved offal as well as meat, dried fish, and butter) “protected” the mutation carriers for almost 300 years until the Icelandic diet changed early in the early 19th century, exemplified by drastic increases in imported carbohydrates and salt.

This finding has implications for studies of Alzheimer’s disease as cerebral amyloid angiopathy (CAA) is almost universally found in Alzheimer’s patients and normal cystatin C protein is one of the proteins found in amyloid in brains of Alzheimer’s patients. Studies are underway to try to elucidate the risk factors with the hope of providing a preventive stategy for cystatin L68Q carriers.

*By deCODE Genetics

Palsdottir A, Helgason A, Palsson S, Bjornsson HT, Bragason BT, et al. A Drastic Reduction in the Life Span of Cystatin C L68Q Carriers Due to Life-Style Changes during the Last Two Centuries. PLoS Genet, 4(6): e1000099 DOI: 10.1371/journal.pgen.1000099

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Know Your Pathology: Spina Bifida

Probably the most common developmental defect reported archaeologically is spina bifida (Roberts and Manchester, 2005: 55). This ‘neural tube defect’ varies in frequency worldwide today, although there are indications that the highest frequencies are found in the British Isles, e.g. 62 of 5607 babies for 1998, and that the lowest frequencies are in Japan, with North America in between (Roberts and Manchester, 2005: 55). Males are more frequently affected than females generally, and genetic and environmental factors are potential causes, these including deficiences in maternal folic acid (vitamin B12), zinc and selenium during foetal development (Roberts and Manchester, 2005: 55).

It is the occulta type, rather than cystica, that is described most frequently (Roberts and Manchester, 2005: 55). Spina bifida occulta is the incomplete fusion of the posterior neural arches of the sacral segments and/or lumbar vertebrae (Roberts and Manchester, 2005: 55). No structures such as the spinal cord protrude out through the space and thus no complications such as infection or paralysis occur (Roberts and Manchester, 2005: 55). In living persons the condition often remains undetected unless X-rays are taken. Spina bifida cystica, on the other hand, is often fatal (Roberts and Manchester, 2005: 55). Three types of severity have been described (Aufderheide and Rodriguez-Martin, 1998: 61):

  • meningocele – involves the protrusion of the nerve roots and meninges through the defect, with the spinal cord remaining in the canal and a covering of skin in place,
  • myelomeningocele – involves the added protrusion of the spinal cord without normal skin covering,
  • myelocele – involves the non-closure of the skin and meninges at the defect, the infection of which usually results in death.

It is unlikely that individuals in the past would have survived such a severe defect, which perhaps explains why there is so little evidence archaeologically (Roberts and Manchester, 2005: 56). If someone did survive, potential complications would include paralysis, incontinence and hydrocephalus (Roberts and Manchester, 2005: 56). For example, a 14-16 year old individual from Florida has been described with spina bifida cystica from lumbar vertebrae 3 to the 2nd sacral vertebrae with subsequent disuse atrophy of some of the bones: this may represent paralysis as a result of the condition (Roberts and Manchester, 2005: 56). More data is available for spina bifida occulta. For the early medieval period in Britain, three sites reporting absolute frequencies (percentage of sacra affected) give frequencies of 8.7% (Roberts and Cox, 2003), while other authors have indicated an average rate of 2.7% for some early British populations (Brothwell and Powers, 1968).

References:

Aufderheide, AC and Rodriguez-Martin, C. 1998. The Cambridge encyclopedia of human palaeopathology. Cambridge: Cambridge University Press.

Brothwell, D and Powers, R. 1968. Congenital malformations of the skeleton in earlier man, pp 173 – 203. In DR Brothwell (ed) Skeletal biology of earlier human populations. Symposia of the Society for the study of Human Biology Volume 8. London: Pergamon Press.

Roberts, C and Cox, M. 2003. Health and disease in Britain: prehistory to the present day. Stroud: Sutton Publishing.

Roberts, C and Manchester, K. 2005. The Archaeology of Disease. Third Edition. Stroud: Sutton Publishing

How long can TB survive?

A note on the environmental persistence (or otherwise) of Mycobacterium tuberculosis in 300-year-old Hungarian mummies can be found over at MicrobiologyBytes.

A trephinated skull from Germany

A review of new research is presented in Nature Precedings regarding a skull radiocarbon dated to 1940 calBC (late Neolithic – early Bronze Age) from Germany, which exhibits signs of trephination.

The authors say:

The skull fragment includes large parts of the cranial vault including both frontal bones down to the left orbital rim, the right parietal, and both occipital regions. The whole cranial base as well as the facial bones and the left temporal regions are missing. It is the only part left of the original skeleton of an adult male. The skull fragment shows two manipulations: In the left frontal-region one notes a hole with a diameter of 30 x 25 mm which results from a funnel-shaped trephination with the outer size of 53 x 50 mm. The diameter of the rim varies from 10 ­ 12 mm. The diploe of the bone is not visible which means that the trephination must have been survived for a longer period of time. The configuration of the defect and the angulation of its edge indicate that the trephination was performed by the scraping-technique. A second defect involves the left occipital region partially crossing the lambdoid suture. It consists of two small and one larger skull fragments which have grown together forming a typical consolidated depressed skull fracture. The depth of the defect is approximately 10 mm at its maximum. Its diameter measures 35 x 24 mm.

They speculate that the individual received two simulataneous injuries, one of which was trephined whilst the second healed without medical intervention. However, as they note, two chronologically differing traumatic incidents are possible of which only one was severe enough to be in need of surgical measures. Alternatively, the intact skull may have been trephined in the left frontal region because of the temporo-occipital injury to prevent complications, e.g. a suspected haematoma under a local bruise of the skin.

Reference: Piek, Juergen, Lidke, Gundula, and Terberger, Thomas. Ancient Trephinations in Neolithic People – Evidence for Stone Age Neurosurgery?. Available from Nature Precedings <http://hdl.handle.net/10101/npre.2008.1615.1&gt; (2008)

Know Your Pathology: Cleft Palate

A cleft palate is a bony defect that is due to the failure of bone union between the two halves of the palate during foetal development. It may be associated with a defect of the upper lip and bone beneath, called the cleft or hare lip (Roberts and Manchester, 2005: 51). The modern incidence of the two conditions is 1 in 700 live births, but of cleft palate alone it is 1 per 1,000 live births (Roberts and Manchester, 2005: 51). Prevalence rates reported for live births for cleft lip with or without cleft palate and cleft palate alone varies within different racial groups.The highest prevalence rates for are reported for Native Americans and Asians. Africans have the lowest prevalence rates (Wikipedia).

The two problems of cleft palate/lip and cleft palate alone are in fact somewhat distinct entities with different causative factors (Roberts and Manchester, 2005: 51). Cases of cleft palate are multifactorial in cause but have a strong family history and are therefore predominantly genetic in origin (Roberts and Manchester, 2005: 51). It is presumed that the problem was probably as common in the past as it is today (and is seen more in females). However, cleft lip frequency does not vary as much as cleft palate among populations and may possibly be more related to environmental influences (Roberts and Manchester, 2005: 51).

Most babies with a cleft lip can be breastfed. However, some babies have difficulty creating a seal around the nipple and may not be able to breastfeed. Cleft palate can also cause problems with speech, tooth development and hearing (because the tube that connects the ear to the palate (the Eustachian tube) can be affected) (BUPA factsheet). Neonates with cleft palate, therefore require potentially time-consuming and laborious care. This may be provided in western societies today, but may have been unacceptable or even impossible in earlier societies, for example, in hunter-gatherer populations (Roberts and Manchester, 2005: 52). Neonatal death of babies with this condition may, therefore, have been common in the distant past. Such deaths may have been motivated by socio-economic attitudes. The respiratory and speech problems that can be associated with cleft palate, in addition to not being able to feed properly and the potential outward disfigurement (for those with cleft lip also) could have attached stigma to, and the ostracism of, people affected, especially in past communities where the condition was little understood (Roberts and Manchester, 2005: 52).

The preservation of fragile neonatal skulls is rarely good enough to allow a diagnosis of cleft palate to be made. Even diagnosing the condition in adult skeletons is fraught with difficulty because of the fragility of the palate bones, and the problem of distinguishing post-mortem breakage from ante-mortem cleft palate (Roberts and Manchester, 2005: 52). There are, however, reported examples from archaeological contexts: a child from 6th-7th century AD Britain, crania exhibiting both cleft palate and hare lip from 2,000-4,000 BP California, and an 11th-12th century AD British male aged 40-50 years old (Roberts and Manchester, 2005: 52).

References:

BUPA Factsheet: http://hcd2.bupa.co.uk/fact_sheets/Mosby_factsheets/cleft_lip.html (accessed April 1, 2008).

Roberts, C and Manchester, K. 2005. The Archaeology of Disease. Third Edition. Stroud: Sutton Publishing

Wikipedia contributors, “Clefting prevalence in different cultures,” Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Clefting_prevalence_in_different_cultures&oldid=201055636 (accessed April 1, 2008).

Trepanation: The Legacy of Ancient Brain Surgery

Jim Myres at Scientific Blogging discusses an interesting history of skull surgery in ‘Trepanation: The Legacy Of Ancient Brain Surgery‘.

What were the chances of surviving the Black Death?

From the latest edition of Current Archaeology (No. 217):

Why did some people survive the Black Death, and others succumb? At the time of the plague – which ravaged Europe from 1347 to 1351, carrying off 50 million people, perhaps half the population – various prophylactics were tried, from the killing of birds, cats and rats to the wearing of leather breeches (protecting the legs from flea bites) and the burning of aromatic spices and herbs.

Now it seems that the best way of avoiding death from the disease was to be fit and healthy. Sharon DeWitte and James Wood of the University of Albany, New York, have examined 490 skeletons from the East Smithfield plague pit in London and found that the Black Death was selective in picking off the already frail. Lesions (damaged bone) associated with earlier episodes of infection, under-nutrition or other forms of physiological stress were present in most of those buried at East Smithfield, where the dead were stacked five deep in the mass graves on a site hurriedly opened on land donated by the Bishop of London.

“This actually contradicts what many have assumed about the epidemic,” says Dr De Witte. “The pattern we observed is of the Black Death targeting the weak, though it did also kill some people who were otherwise healthy. This is consistent with an emerging disease striking a population with no immunity.”