1　临床资料患者,男,23a,因双眼视力下降3mo余而入院。患者自幼视力不好,14a时即戴-8.00D眼镜。近3mo来视力显著下降已影响生活。其父高168cm,母高152cm。其祖父身材瘦长(180cm左右),有心脏病史,70a时不明原因去世。查体:一般情况好,智力较差。身高143cm,体重52kg,较同年龄者显 1 clinical data patients, male, 23a, due to binocular vision decreased 3mo more than admitted. Patients with poor vision since childhood, 14a wear -8.00D glasses. The past 3 months to a significant decline in visual acuity has affected life. His father height 168cm, female height 152cm. His grandfather was slender (around 180cm) with a history of heart disease and passed away for unknown reasons at 70a. Physical examination: the general situation is good, mental retardation. Height 143cm, weight 52kg, more significant than the same age