Symptomatic Generalized Hypomobility Is Associated With Abnormal Collagen

[Guest guest]

Symptomatic Generalized Hypomobility Is Associated With Abnormal Collagen

By Karla Gale

NEW YORK (Reuters Health) Apr 05 - Clinicians in the Netherlands have

identified a condition in children, symptomatic generalized hypomobility,

which appears to be caused by abnormal collagen metabolism.

Dr. Raoul H. H. Engelbert and colleagues identified 19 white children with

joint hypomobility, exercise-induced pain and/or habitual toe-walking. The

mean age of the patients was 11.6 years old. According to their report in

the April issue of Pediatrics, the patients exhibited no overt signs of

rheumatic, neurologic, skeletal, metabolic or connective tissue disorders.

" These patients had already visited pediatricians, orthopedic surgeons and

pediatric rheumatologists, who could not find answers for their complaints, "

Dr. Engelbert, a physical therapist at Wilhelmina Children's Hospital in

Utrecht, told Reuters Health. As a result, " they were frequently sent to

physiotherapists, but treatment had no more than short-term results. "

The range of active joint motion was significantly reduced in almost all

joints compared with a reference group of 274 children. Fourteen exhibited

habitual toe-walking, and exercise-induced pain was reported by 13 patients.

Quantitative bone ultrasound measurements in 16 patients revealed reduced

broadband ultrasound attenuation and speed of sound, which remained

statistically significant after adjustment for age, gender, height and

weight. However, there was no long-term immobility or increased bone

remodeling, and muscle strength was normal.

The authors also observed a lower amount of collagen degradation products in

the urine compared with the reference group. In skin biopsies obtained from

three children, there were increased cross-links per collagen molecule and

increased ratios of collagenous to noncollagenous proteins, suggesting an

increased amount of collagen.

Dr. Engelbert commented that complaints tended to " increase during growth

spurts (about the age of 4, 6 through 7 and puberty) probably due to a

mismatch in growth of the osseal and soft tissue structures. "

Although there are no published reports of a similar condition in adults,

" almost all fathers and some mothers reported the same complaints as their

children, " so " I am sure that there is a genetic component associated with

generalized hypomobility. "

" Depending on their complaints, short-term therapy may be indicated, " he

added. " We do not think that stretching the tight muscles will influence

mobility. We sometimes advise [patients] to walk with the back of the foot

elevated about 1 to 2 cm (mimicking toe-walking)...to avoid overuse of the

musculoskeletal system. "

" More basic research is warranted, " as well as studies on long-term outcomes

because other organ systems may be affected, he added.

Pediatrics 2004;113:714-719.