Pediatric MS in The Netherlands

Epub ahead of print: Ketelslegers et al. Incidence of acquired demyelinating syndromes of the CNS in Dutch children: a nationwide study. J Neurol. 2012 Feb 17.

Acquired demyelinating syndromes (ADS) can be a first presentation of MS in children. The incidence of these disorders in Europe is currently unknown. Children (<18 years old) living in the Netherlands who presented with ADS were included from January 1, 2007 to December 31, 2010 by the Dutch pediatric MS study group and the Dutch surveillance of rare pediatric disorders. Personal and clinical data were collected. 86 patients were identified over 4 years, resulting in an incidence of 0.66/100,000 per year.

“This compares with an adult incidence of MS of ~6-7/100,000 per year.”

Most patients presented with polyfocal ADS without encephalopathy (30%), followed by polyfocal ADS with encephalopathy (24%), optic neuritis (ON, 22%), monofocal ADS (16%), transverse myelitis (3%), and neuromyelitis optica (3%).

“Encephalopathy essentially means confusion or delirium; this is very rare in adult-onset disease.”

Patients with polyfocal ADS with encephalopathy were younger (median 3.9 years) than patients with ON (median 14.6 years, p < 0.001) or monofocal ADS (median 16.0 years, p < 0.001). Patients with polyfocal ADS without encephalopathy (median 9.2 years) were also younger than monofocal ADS patients (median 16.0 years, p < 0.001). There was a slight female preponderance in all groups except the ON group, and a relatively large number of ADS patients (29%) reported a non-European ancestry. Familial autoimmune diseases were reported in 23%, more often in patients with relapsing disease than monophasic disease (46 vs. 15%, p = 0.002) and occurring most often in the maternal family (84%, p < 0.001).

“This transmission down the maternal line (mother) is very interesting and is not necessarily due to genetic factors (inheritance of DNA) but could imply epigenetic events due to alterations of how the DNA is controlled (see previous posting on this topic).”

During the study period, 23% of patients were subsequently diagnosed with MS. The annual incidence of ADS in the Netherlands is 0.66/100,000 children/year. A polyfocal disease onset of ADS was most common.

“This study makes you realise how uncommon MS is children and how difficult it can be to make the diagnosis. It is clear that older children have a disease that is similar to adults, compared to smaller children who tend have a different presentation. By studying paediatric MS we should get an idea of the earliest events that cause MS and may be a way of getting to the cause of the disease.”

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