Is Sanfilippo type B in your mind when you see adults with mental retardation and behavioral problems?
Sanfilippo type B is an autosomal recessive mucopolysaccharidosis (MPS IIIB) caused by deficiency of N-acetyl-alpha-D-glucosaminidase, a lysosomal enzyme involved in the degradation of heparan sulfate. It is characterized by neurologic degeneration, behavioral problems, and mental decline. Somatic features are relatively mild and patients with this disorder can reach late adulthood. It is the most common subtype of MPS in the Netherlands and probably underdiagnosed in adult persons with mental retardation (MR). In order to increase knowledge on the adult phenotype and natural history in Sanfilippo type B, we present the clinical data of 20 patients with this disorder. Sixteen of them were followed for one to three decades. Six died between 28 and 69 years of age, mainly from pneumonia and cachexia; the surviving patients were 18-63 years old. Apart from the youngest, they had lost mobility at 36-68 years. Most had developed physical problems, in particular in the 4th-6th decade of life: cardiac disease (cardiomyopathy, atrial fibrillations), arthritis, skin blistering, swallowing difficulties requiring feeding by a gastrostomy tube, and seizures. The course of the disease was dominated in most of them by challenging behavioral problems with restlessness, extreme screaming and hitting, difficult to prevent or to treat pharmaceutically. Even in absence of knowledge of the history of an elderly patient with MR, the presence of behavioral problems should prompt metabolic investigation for MPS.
Moog
Ute
U
Department of Clinical Genetics, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. ute.moog@med.uni-heidelberg.de
van Mierlo
Ingrid
I
van Schrojenstein Lantman-de Valk
Henny M J
HM
Spaapen
Leo
L
Maaskant
Marian A
MA
Curfs
Leopold M G
LM
D000293:Adolescent; D000328:Adult; D001526:Behavioral Symptoms / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009084:Mucopolysaccharidosis III / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology