本文报道了一例两条9号染色体次缢痕缺失的女性病例,临床表现为严重智力低下和语言障碍。经外周血淋巴细胞染色体G、C显带分析,确定其核型为46,XX,del(9)del(9)(pter→q11∷q13→qter)。又对其父母及妹妹进行了染色体分析,患者之父与两个妹妹的核型均正常,其母是46,XX,del(9)(pter→q11∷q13→qter)核型的携带者。 In this paper, we report a case of two female cases of absence of secondary scar on chromosome 9, with severe mental retardation and speech impairment. The peripheral blood lymphocytes chromosome G, C banding analysis to determine the karyotype of 46, XX, del (9) del (9) (pter → q11 :: q13 → qter). Chromosome analysis was performed on parents and sisters. The karyotype of the father and two sisters of the patient were both normal and their mothers were carriers of karyotype 46, XX, del (9) (pter → q11 :: q13 → qter).