Evidence emerging of a new hereditary joint disorder

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Evidence emerging of a new hereditary joint disorder



Oct 17, 2005



Gandey

Cleveland, OH - Researchers are unveiling what they say is the first

evidence of a new hereditary cartilage debonding syndrome [1].

Investigators in the October 2005 issue of Arthritis and Rheumatism

outline this destructive joint disorder, which is characterized by

cartilage prone to bubbling and peeling away from the bone. " We

report clinical and laboratory findings of a family with a previously

undescribed hereditary cartilage debonding syndrome, " comment the

researchers, led by Dr Holderbaum (Case Western Reserve

University, Cleveland, OH).



This syndrome began as early as the first decade of life and is

characterized by friability of articular cartilage with debonding of

cartilage from subchondral bone.



The investigators assessed a family with symptoms of the highly

unusual and damaging condition. Those affected had multiple shoulder,

hip, and knee arthropathies that began in the preteen years and

continued into adulthood. Various diagnoses had been suggested,

including spondyloepiphyseal dysplasia and Osgood-Schlatter disease.

" In affected family members, this syndrome began as early as the

first decade of life and is characterized by friability of articular

cartilage with debonding of cartilage from subchondral bone, "

Holderbaum and colleagues explain. " The affected family members

underwent multiple arthroscopic procedures for diagnostic and

therapeutic purposes, and three of four subjects underwent total

joint replacement during the third to sixth decades of life. "

Could it be . . .

Spondyloepiphyseal dysplasia?

Multiple epiphyseal dysplasia?

Legg-Calvé-Perthes disease?

Osgood-Schlatter disease?



Holderbaum and his team collected blood samples from the affected

proband father, his three affected children, and healthy family

members. They examined the samples for single-nucleotide

polymorphisms (SNPs) in the chromosome 2 region, including the

Frizzled-related protein gene and a soluble Wnt protein-signaling

antagonist that influences bone and cartilage development.



The clinical findings reported here represent a newly defined

clinical syndrome characterized by marked cartilage friability and

osteochondral debonding.



The investigators found that each of the affected family members had

clear similarities, including effusions, large loose bodies, and

bubbling and delamination of the cartilage with exposure of

subchondral bone. Those affected also had radiographic changes in the

hip, including femoral-head flattening and secondary degenerative

arthritis. They also showed abnormalities in the physical properties

of the cartilage that were apparent on arthroscopic examination.

Holderbaum and colleagues identified two SNPs in the family members

with symptoms of disease. Interestingly, the researchers point out,

these were also present in certain unaffected relatives, including

the proband's mother and two of his four unaffected siblings.

" Because unaffected family members also have this change in

presumptive amino-acid sequence, it is clear that this mutation is,

in and of itself, insufficient to cause the phenotype, " they write.

" Whether the mutation plays a role in what could be a polygenic trait

responsible for the phenotype remains to be seen. "

They conclude that these findings represent a newly defined clinical

syndrome characterized by marked cartilage friability and

osteochondral debonding. They call for additional studies elucidating

the mechanism leading to the delamination of cartilage from bone,

which may provide insight into cartilage-bone interaction in other

forms of joint degeneration.

Source



Holderbaum D, Malvitz T, Ciesielski CJ, et al. A newly described

hereditary cartilage debonding syndrome. Arthritis Rheum 2005;

52:3300-3304.

http://www.jointandbone.org/viewArticle.do?primaryKey=577383