Until recently a definite diagnosis of Huntington's disease could
be made by a combination of clinical findings, a positive family history, and pathological confirmation. Prevalence data are
based on these criteria. After finding the gene and its pathogenic mutation direct diagnostic confirmation became available.
aim of this study was to determine to what extent the direct assessment of CAG repeat length has allowed the diagnoses of
additional patients, with atypical psychiatric or neurological disease, or those without a family history, that could otherwise
not be diagnosed using traditional criteria.
PATIENTS AND METHODS
all 191 referred patients suspected of having Huntington's disease between July 1993 and January 1996 CAG repeat length was
determined and the family history was reviewed in the Leiden roster.
After a retrospective search the patients were
subdivided in positive, negative, suspect, and unknown family histories. Patients with an expanded repeat (>35) were finally
diagnosed as having Huntington's disease. The family history was compared with the repeat length and the clinical features.
was obtained for 172 patients. Of these, 126 patients had an expanded repeat, 77 had a positive, eight a negative, 40 a suspect,
and one an unknown family history.
Of the 44 patients with a normal repeat length four had a positive family history.
Of the two patients with an intermediate repeat (between 30-36 repeats), one with a negative family history received a clinical
diagnosis of Gilles de la Tourette's syndrome. The other had an unknown family
of the family history through the Leiden roster, many more patients and families could be diagnosed with the new approach
than would have been possible with the traditional criteria. Because prevalence studies have been based on this type of information,
the data suggest an underestimation of the prevalence of Huntington's disease in the community of 14%.
(J Neurol Neurosurg Psychiatry 2000;69:54-59)
S Sieslinga, M Vegter-van de Vlisb,
M Losekootb c, R D M Belfroidc, J A Maat-Kievitb, H P H Kremerd, R A C Roosaa
Department of Neurology, K5Q-112 Leiden University Medical Centre, PO Box 9600,
2300 RC Leiden, The Netherlands, Centre for Clinical Genetics, cDepartment of
Human Genetics, Department of Neurology, Radboud Hospital, Nijmegen, The Netherlands.
Correspondence to: Professor R A C Roos R.A.C.Roos@LUMC.NL
Source: J Neurol Neurosurg Psychiatry 2000;69:54-59 ( July )