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Fibrous Dysplasia & McCune-Albright Syndrome

28 Oct

Definition of Fibrous Dysplasia: ‘Fibrous dysplasia is a non-inherited metabolic bone disease in which abnormal differentiation of osteoblast maturation (which) leads to replacement of normal marrow and cancellous bone by immature bone and fibrous stroma’ (Fitzpatrick et al 2004: 1389).  Fibrous Dsyplasia (FD) can be described as either monostotic (one) or polyostotic (many), depending on how many bones are affected by the disease.  Fibrous Dysplasia lesions are often displayed as having a ‘ground glass‘ appearance on x-rays and are a distinctive radiographic feature of the disease, although it is not pathognominic of it (Waldron 2009).  It is also noted that pathological fractures are a key defining feature of polyostotic Fibrous Dysplasia (Marsland & Kapoor 2008).  FD is described as a rare disease, with the monostotic form being more prevalent than the polyostotic form.

Definition of McCune-Albright Syndrome:  McCune-Albright Syndrome (MAS) was originally typically diagnosed and recognised when a person had any of the two of the triad of the following symptoms: polyostotic Fibrous Dysplasia, Cafe-au-lait marks and/or precocious puberty.  However it was later recognised that ‘endocrinopathies, including hyperthyroidism, growth hormone excess, renal phosphate wasting with or without rickets/osteomalacia, and Cushing Syndrome’  could be found in association with the original triad (Dumitrescu & Collins 2008: 1).  In all three systems (skin, skeletal & endocrine), the presentation and abnormality can be highly variable from person to person depending on the tissues involved and the extent of the involvement (OMIM-see below).  Estimated prevalence is 1/100,000 to 1/1,000,000, it is such a wide margin because no thorough prevalence study has been carried out in recent times (Dumitrescu & Collins 2008: 1).

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As a person who happens to have McCune Albright syndrome, to have known to have it from the first years of life, I have become somewhat forgetful of its origin: that somewhere in the early post-zygotic  divisions of my life, the disease appeared and became a part of me.  Although I am aware each day of the ramifications that the mutation of the GNAS1 gene has caused I often consider myself lucky.  Lucky in the fact that in my case it has only led to broken bones and various surgeries rather than the full expression of the endocrinopathies that can occur.  I use a wheelchair for everyday mobility with limited use of crutches, mostly used for aiding inside mobility (and sometimes excavations!).

In my personal case, the disease has most affected the main weight-bearing bones of the lower limbs (fairly typical as they are the stress bearing bones, prone to fracture from weakened bone architecture).  Generally speaking,the long bones of the appendicular skeleton tend to be bowed naturally with a pathological weakness due to the lack of normal bone density and high bone cell turnover, with the aforementioned bone lesions occurring spontaneously which sometimes lead to fracture.  This includes the bilateral deformity of the femora with which I’ve had numerous pathological fractures (5 natural transverse fractures, 5 surgery initiated) on both the left and right sides, alongside a number of fractures of the right tibia and fibula (including both transverse and hairline fractures), right humerus and the 5th metatarsal in the right foot.  The ‘shepherd’s crook deformity‘ is the common bowing deformity with varus angulation of the proximal femur‘  (Fitzpatrick et al 2004: online).  As stated the primary bones affected by the MAS pathological fractures are typically located in the appendicular skeleton and include the following bones in order of prevalence first:  a) Femora, b) Tibiae, c) Fibulae, d) Humeri and e) the Ribs.  It can also affect the craniofacial skeleton with distinct abnormalities in the amount of bone growth and deformity; however this tends to lessen with age after the primary and secondary growth periods (adolescence and sexual maturity), or ‘burn out’ as it is often called by medical specialists (Dumitrescu & Collins 2008: 8).

‘An example of the shepherds crook’ deformity of the femoral neck (coxa vara) with internal fixation.

My experiences of living with McCune Albright syndrome has included numerous hospitalizations due to fractured bones and planned corrective surgeries.  This has also included large amounts of time stuck in my old friend the Thomas Splint in bed bound traction, alongside enduring a host of various corrective surgical procedures to improve the angulation of both femoral necks.  Although the initial idea was to treat the femoral deformity with an Ilizarov apparatus by manipulating the bone growth every day, it was quickly decided that an intramedullary rod (nicknamed the Sheffield Rod), carried out in conjunction with osteotomies to correct the femoral neck angle during surgery, would be a much safer and further reaching goal in stabilising both femoral necks in the long term.  (A rather wonderful digital video of a rod being inserted/hammered in can be viewed here).  Five major intramedullary rod surgeries later (3 for the left femur and 2 for the right femur!), and it seems as if they have thus far stabilised each femoral shaft/neck enough for them not to fracture again.  However this is also due to using the wheelchair much more extensively than before!

I  also have had surgery to stabilise the right tibia and fibula.  This was decided after having undergone 3 accidental fractures of the right tibia and fibula with a space of 5 years (when the tibia breaks the fibula often follows because of their connection via the interosseous membrane), with each fracture requiring many months in plaster in order for the bone to heal.  Again this surgery included osteotomies of the tibia and fibula to improve the angle of the bone (and thus improve the bio-mechanical loading of the lower leg) and included the fixation of the tibia by means of a titanium plate.  It was hoped that an intramedullary rod could be inserted into the tibia after the tibial osteotomy but the risk of massive blood loss (an outcome of the porous bone and increased heartbeat/blood flow) and the presence of porous cortical bone meant that the tibia was probably unlikely to be able to ‘hold’ the rod in place.

I have undertaken treatment using biphosphonphates (in my case the drug pamidronate) to increase the bone density itself over a number of years in the past when I was a teenager, but the resultant bone density scans (taken at intervals during the treatment) showed little improvement and treatment was subsequently stopped.  Upon further reading into this it seems there are possible problems for long term users of biphosphonates.   This can include the higher risk of fracture after long term use due to the bodies inability to metabolize the drug and the natural effect of the biphosphonate inhibition on the bone cell turnover rate (Ott 2005: 31897).  There are many cases though where drug treatment has proved beneficial; however each case should be merited individually and each person monitored as appropriate.  I will stress here that there are many different types of biphosphonates available and that McCune Albright Syndrome varies in its intensity.

My left femur and hip with a locking intramedullary rod and screws.

Although this is just a short post on the introduction to the disease that is sharing life with me it can also be found in the archaeological record.  Waldron (2009: 214) points out that Fibrous Dysplasia is often best diagnosed in an archaeological skeleton by the noting of either a shepherd’s crook deformity, healed fractures and findings of expansile swellings on one or more bones.  Subjecting the suspected sample to X-ray should show ‘lucent areas with endosteal scalloping and sometimes a thick sclerotic border’  (Waldron 2009: 215).  Unlike today’s vast array of modern medical treatment and surgical procedures, people in the past largely had to make do and mend.  As Roberts & Manchester (2010) discuss in their book, fracture treatment in the medieval age and before was fairly adept at helping in supporting and stabilising the fracture site.  However with repeated breaks in the main weight supporting bones, it is doubtful whether one could have led a normal life if the fractures were not reduced properly or repeatedly after continual breaks (Oakley 2007).  It also should be noted here that due to the nature of McCune Albright Syndrome it is unlikely to be described in the archaeology record as human skin rarely preserves.  It is far more likely that Fibrous Dysplasia is diagnosed based on the skeletal remains.

In the archaeological record Fibrous Dysplasia remains a rare and elusive disease to diagnose, whilst is has actively been described and documented in more recent human remains (Nerlich et al. 1991).  The following two case studies highlight individual cases of where Fibrous Dysplasia has been documented in archaeological material:

A recent case study presented by Craig & Craig (2011) discusses a juvenile skeleton with evidence of polyostotic Fibrous Dysplasia.  The skeletal remains of a child aged 7 years presents with Fibrous Dysplasia with evidence of involvement most noticeable with large bone expansion on the left mandible alongside involvement of the temporal, maxilla, parietal and frontal craniofacial bones.  A review of the burial context of the skeleton and of the Anglo-Saxon cemetery population that the child comes from shows no differentiation between this and other burials, indicating no differentiation in the disposition of this child’s body or associated grave goods.  Craig & Craig (2011) also cite further Ango-Saxon literature to suggest that it is highly unlikely that the child was stigmatized due to his disability, although we can never know for sure.

Recent evidence in a 120,000 year old Neandertal individual from the Upper Pleistocene site of Krapina in present day Croatia highlights the likely evidence for Fibrous Dysplasia presence in a small rib fragment (Monge et al. 2013).  This is extremely rare to find a bone lesion or tumour  in skeletal material from such a period and it is extremely exciting.  The rib was allocated original as a faunal remain when the site was initially excavated, but the rib was recognised for being of Neandertal origin by sharp eyed human osteology legend Tim D. White (Monge et al. 2013).

A transverse fracture of my right tibia and fibula in the summer of 2009.

Below are some medical and non-medical sources of information on the various aspects of both Fibrous Dysplasia & McCune Albright Syndrome (FD and MAS). This includes a few recent palaeopathology articles that are freely available, medical articles discussing both FD and MAS, core palaeopathology textbooks and support groups in the US and UK for sufferers of the bone disease.  Although the disease is not headline grabbing news, the lack of research into the socio-economic aspects of the disease is distinctly lacking, as is the number of foundations or adult support services for sufferers with the disease.

I am thankful for the support of my friends, family & my consultant in the treatment of this syndrome and for continued support given.

N.B. The origin of the Ilizarov frame is particularly interesting.  It was first used in the 1950s in the USSR, with Dr Gavril Ilizarov originally using bicycle wheel spokes to fixate, support and lengthen badly fractured bones.  It was only introduced to the West in the 1980′s as a direct result of Ilizarov’s corrective surgery on a patient in Italy when all other options had failed in healing the patient’s fractures.  So far I have managed to avoid having the frame but it is still a standard procedure for badly fragmented fractures, in particular it is often used after motorbike accidents or reconstructing limb angulation/length.

Bibliography and Further Sources:

Fibrous Dysplasia:

McCune-Albright Syndrome:

Palaeopathology:
General Medical
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