van Karnebeek Clara D M, Jansweijer Maaike C E, Leenders Arnold G E, Offringa Martin, Hennekam Raoul C M
Department of Paediatrics/Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands.
Eur J Hum Genet. 2005 Jan;13(1):6-25. doi: 10.1038/sj.ejhg.5201279.
There are no guidelines available for diagnostic studies in patients with mental retardation (MR) established in an evidence-based manner. Here we report such study, based on information from original studies on the results with respect to detected significant anomalies (yield) of six major diagnostic investigations, and evaluate whether the yield differs depending on setting, MR severity, and gender. Results for cytogenetic studies showed the mean yield of chromosome aberrations in classical cytogenetics to be 9.5% (variation: 5.4% in school populations to 13.3% in institute populations; 4.1% in borderline-mild MR to 13.3% in moderate-profound MR; more frequent structural anomalies in females). The median yield of subtelomeric studies was 4.4% (also showing female predominance). For fragile X screening, yields were 5.4% (cytogenetic studies) and 2.0% (molecular studies) (higher yield in moderate-profound MR; checklist use useful). In metabolic investigations, the mean yield of all studies was 1.0% (results depending on neonatal screening programmes; in individual populations higher yield for specific metabolic disorders). Studies on neurological examination all showed a high yield (mean 42.9%; irrespective of setting, degree of MR, and gender). The yield of neuroimaging studies for abnormalities was 30.0% (higher yield if performed on an indicated basis) and the yield for finding a diagnosis based on neuroradiological studies only was 1.3% (no data available on value of negative findings). A very high yield was found for dysmorphologic examination (variation 39-81%). The data from this review allow conclusions for most types of diagnostic investigations in MR patients. Recommendations for further studies are provided.
目前尚无基于循证医学方法制定的针对智力发育迟缓（MR）患者的诊断性研究指南。在此，我们基于六项主要诊断性检查结果（检测到的显著异常情况，即“阳性率”）的原始研究信息进行此类研究，并评估阳性率是否因研究背景、MR严重程度及性别而异。细胞遗传学研究结果显示，经典细胞遗传学中染色体畸变的平均阳性率为9.5%（变化范围：学校人群中为5.4%，机构人群中为13.3%；边缘 - 轻度MR中为4.1%，中度 - 重度MR中为13.3%；女性结构异常更常见）。亚端粒研究的中位阳性率为4.4%（同样显示女性占优势）。对于脆性X筛查，阳性率分别为5.4%（细胞遗传学研究）和2.0%（分子学研究）（中度 - 重度MR中阳性率更高；使用检查表有用）。在代谢检查中，所有研究的平均阳性率为1.0%（结果取决于新生儿筛查项目；在个体人群中，特定代谢紊乱的阳性率更高）。神经学检查研究均显示阳性率较高（平均42.9%；与研究背景、MR程度及性别无关）。神经影像学检查异常的阳性率为30.0%（按指征进行检查时阳性率更高），仅基于神经放射学研究做出诊断的阳性率为1.3%（关于阴性结果的价值无可用数据）。畸形学检查的阳性率非常高（变化范围为39 - 81%）。本综述的数据有助于得出关于MR患者大多数类型诊断性检查的结论。还提供了进一步研究的建议。
