Fisch G S, Simensen R, Tarleton J, Chalifoux M, Holden J J, Carpenter N, Howard-Peebles P N, Maddalena A
Kings County Hospital Center, Brooklyn, New York, USA.
Am J Med Genet. 1996 Aug 9;64(2):356-61. doi: 10.1002/(SICI)1096-8628(19960809)64:2<356::AID-AJMG24>3.0.CO;2-D.
Retrospective longitudinal studies have noted declines in IQ scores in many but not all fra(X) (fragile X) males and females. We report on a prospective investigation of longitudinal changes in cognitive ability (IQ) and adaptive behavior (DQ) in 24 fra(X) males from four test sites. Individuals who were tested ranged in age from 3-15 years. To determine cognitive ability, all males were administered the Stanford-Binet test (4th Edition). To assess adaptive behavior, all males were evaluated using the Vineland Adaptive Behavior Scales. Mean interest interval was 2.3 years. Using identical DNA protocols, all subjects were identified as bearing the fra(X) mutation. Results showed declines in IQ scores in 18/24 (75%) males. Four males showed no change in scores. Declines in DQ scores were noted in 22/24 (92%) of those tested. DQ scores were higher than IQ scores in 20/24 (83%) subjects. From a descriptive cohort analysis, decreases in IQ scores appear to follow a well-defined, negatively decelerating function. Declines in DQ were steeper and more nearly linear. Declining scores are not indicative of regression of intellectual and/or social skills, but of a relative inability to keep pace with their age-normed cohort. We conclude that the fra(X) mutation affects cognitive abilities in a uniform, nonlinear manner comparable to outcomes observed in earlier retrospective studies. Adaptive behavior also declines, but in a more linear fashion.
回顾性纵向研究指出，许多（但并非所有）脆性X综合征（fra(X)）男性和女性的智商分数有所下降。我们报告了一项对来自四个测试地点的24名脆性X综合征男性认知能力（智商）和适应性行为（发育商）纵向变化的前瞻性调查。接受测试的个体年龄在3至15岁之间。为了确定认知能力，所有男性都接受了斯坦福-比奈智力量表（第4版）测试。为了评估适应性行为，所有男性都使用文兰适应性行为量表进行了评估。平均观察间隔为2.3年。使用相同的DNA检测方法，所有受试者均被确定携带脆性X综合征突变。结果显示，18/24（75%）的男性智商分数下降。4名男性的分数没有变化。在22/24（92%）接受测试的男性中，发育商分数下降。20/24（83%）的受试者发育商分数高于智商分数。从描述性队列分析来看，智商分数的下降似乎遵循一个明确的负减速函数。发育商的下降更为陡峭且更接近线性。分数下降并不表明智力和/或社交技能的退化，而是表明相对无法跟上同龄人按年龄标准化的水平。我们得出结论，脆性X综合征突变以一种统一的、非线性方式影响认知能力，这与早期回顾性研究中观察到的结果类似。适应性行为也会下降，但呈更线性的方式。
