TY - JOUR
T1 - Cognitive impairment and (CTG)n expansion in myotonic dystrophy patients
AU - Perini, Giulia I.
AU - Menegazzo, Elisabetta
AU - Ermani, Mario
AU - Zara, Michele
AU - Gemma, Andrea
AU - Ferruzza, Emilia
AU - Gennarelli, Massimo
AU - Angelini, Corrado
PY - 1999/8/1
Y1 - 1999/8/1
N2 - Background: Myotonic dystrophy (DM) is a genetic multisystemic disease with muscular, endocrine, ocular, cardiac and cognitive impairment. The molecular basis of the disease has been identified in an unstable base triplet (CTG)n repeat located in the 3' untranslated region of the miotonin protein-kinase (MT-PK) gene on the long arm of chromosome 19. Cognitive impairment could be a direct expression of this genetic alteration at the central nervous system (CNS) level rather than a consequence of the neuromuscular impairment. To explore this hypothesis, we tested a group of genetically diagnosed, adult onset DM, of their nonaffected relatives (NAR), of patients with spinal muscle atrophy (SMA), and of normal controls using the Wechsler Adult Intelligence Scale (WAIS). Methods: Seventeen adult-onset DM patients, 9 NAR, 10 SMA patients and 20 unrelated normal controls (NC) were studied. Clinical, neuromuscular and neuropsychiatric evaluation, which included WAIS and the Schedule for Affective Disorders and Schizophrenia (SADS), were performed on the four groups. DM, NAR and NC were also assessed by a neurophysiological (P300) evaluation. A DNA analysis was performed in DM and in NAR to measure presence and magnitude of CTG expansion. Results: We found a statistically significant difference between verbal (p <.0003), nonverbal (p <.0001) and total (p <.0001) IQ of DM patients compared to IQs of NAR, SMA and NC. Seven out of 11 WAIS subtests were significantly and consistently lower in DM patients compared to SMA and/or NC. In DM patients there was a statistically significant negative correlation between nonverbal (r = - .68; p <.002) and total (r = .59; p <.01) IQ and (CTG)n. Patients with DM had a significantly lower P300 amplitude compared to NAR and NC. Conclusions: Our study indicates that in DM there is a mild but significant cognitive impairment which correlates with the degree of CTG expansion and it is not dependent on the neuromuscular impairment; however further studies with larger groups of patients and controls are suggested to confirm our results, due to the small sample size and to a possible effect of educational level in our patients. Copyright (C) 1999 Society of Biological Psychiatry.
AB - Background: Myotonic dystrophy (DM) is a genetic multisystemic disease with muscular, endocrine, ocular, cardiac and cognitive impairment. The molecular basis of the disease has been identified in an unstable base triplet (CTG)n repeat located in the 3' untranslated region of the miotonin protein-kinase (MT-PK) gene on the long arm of chromosome 19. Cognitive impairment could be a direct expression of this genetic alteration at the central nervous system (CNS) level rather than a consequence of the neuromuscular impairment. To explore this hypothesis, we tested a group of genetically diagnosed, adult onset DM, of their nonaffected relatives (NAR), of patients with spinal muscle atrophy (SMA), and of normal controls using the Wechsler Adult Intelligence Scale (WAIS). Methods: Seventeen adult-onset DM patients, 9 NAR, 10 SMA patients and 20 unrelated normal controls (NC) were studied. Clinical, neuromuscular and neuropsychiatric evaluation, which included WAIS and the Schedule for Affective Disorders and Schizophrenia (SADS), were performed on the four groups. DM, NAR and NC were also assessed by a neurophysiological (P300) evaluation. A DNA analysis was performed in DM and in NAR to measure presence and magnitude of CTG expansion. Results: We found a statistically significant difference between verbal (p <.0003), nonverbal (p <.0001) and total (p <.0001) IQ of DM patients compared to IQs of NAR, SMA and NC. Seven out of 11 WAIS subtests were significantly and consistently lower in DM patients compared to SMA and/or NC. In DM patients there was a statistically significant negative correlation between nonverbal (r = - .68; p <.002) and total (r = .59; p <.01) IQ and (CTG)n. Patients with DM had a significantly lower P300 amplitude compared to NAR and NC. Conclusions: Our study indicates that in DM there is a mild but significant cognitive impairment which correlates with the degree of CTG expansion and it is not dependent on the neuromuscular impairment; however further studies with larger groups of patients and controls are suggested to confirm our results, due to the small sample size and to a possible effect of educational level in our patients. Copyright (C) 1999 Society of Biological Psychiatry.
KW - Cognitive deficits
KW - Evoked potential CTG amplification
KW - Myotonic dystrophy
KW - Spinal muscle atrophy
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U2 - 10.1016/S0006-3223(99)00016-5
DO - 10.1016/S0006-3223(99)00016-5
M3 - Article
C2 - 10435210
AN - SCOPUS:0032765607
VL - 46
SP - 425
EP - 431
JO - Biological Psychiatry
JF - Biological Psychiatry
SN - 0006-3223
IS - 3
ER -