摘要:

AbstractPrenatal diagnosis is now available to fragile X (fra[X]) syndrome families and has proven reliable when testing male fetuses. It has been reported that approximately one‐third of heterozygous fra(X) females demonstrate mental impairment. Based on this, families usually continue pregnancies involving a female fetus. The purpose of this study is to investigate whether a 35% risk for mental impairment is appropriate when counseling heterozygous women carrying fra(X)‐positive female fetuses. Forty‐three cytogenetically positive (≥2%) daughters of known fra(X) carrier women were ascertained postnatally in an unbiased fashion. Their mother's carrier status was determined on the basis of at least one son with Martin‐Bell syndrome. In addition to peripheral blood cytogenetic studies, all daughters had cognitive testing to determine full‐scale IQ. In this study, 55.8% (24/43) were mentally impaired (IQ<85) compared with the expected 35%. Of these, 42% were mentally retarded (IQ<70). Although we do not know the correlation between percent fragility by peripheral blood compared with the percent fragility by amniocentesis or CVS, we assume that they are relatively comparable such that a female who is positive with ≥2% fragility would probably be positive by all methods. This report suggests that the penetrance of mental impairment in females with a percent fragility of ≥2% may be as high as 55%. Further studies are necessary to clarify this issue so that accurate information can be given in gen

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380272

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractCognitive deficits in females with fragile X [fra(X)] syndrome have been reported, but studies have rarely focused on women with normal intelligence, nor have they separated fra(X)‐negative carriers from fra(X)‐positive carriers. Questions specifically addressed here are: (1) is the degree of fragility predictive of IQ? (2) are cognitive patterns consistent across fragility levels? and (3) do consistent individual profiles exist? These questions were addressed with the help of 74 heterozygous women, 38 of whom were fra(X)‐negative carriers. All women completed the WAISR, and full‐scale IQ was normally distributed (mean = 99.65). A strong inverse relationship between IQ and fragility levels was found. Also, the group of fra(X)‐positive women had a significantly different subtest pattern from that of the fra(X)‐negative women. However, when results were analyzed individually, no consistent patterns emerged. The cognitive performance of fra(X)‐negative carriers has probably been underestimated due to the lack of differentiation between positive and negative carrier females in previous studies. These women appear to be cognitively unimpaired and should be considered separately from fra(X)‐positive women. Since consistent WAIS‐R patterns are not observable on an individual basis, their use as a diagnostic/predictive tool appears to

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380273

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380274

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380275

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes EEG and clinical findings resulting from a follow‐up investigation in a group of 18 males with fragile X syndrome, in whom a characteristic paroxysmal EEG pattern was previously described. The following types of evolution were observed: (1) disappearance of the pattern (with a gradual lowering of the amplitude of spikes and in some cases with asynchrony between the two hemispheres); (2) disappearance of the quasirhythmic centrotemporal spikes and persistence of bisynchronous polyspike and wave complexes in the temporo‐parieto‐frontal regions; and (3) persistence of the previously observed pattern. These results confirm the already observed similarity between this condition and the benign childhood epilepsy with centrotemporal spikes, also from the maturational point of view; on the other hand, they also indicate some difference (i.e., mental retardation, slow background EEG activity, brain atrophy). Moreover, these findings are encouraging for the possible development of research in the field of molecular genetics in epilepsy, because they provide a precise site of investigation on the X chrom

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380276

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380277

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

ISSN:0148-7299    

DOI:10.1002/ajmg.1320380201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY