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1、21三体综合征 我国每年大约有我国每年大约有26,60026,600个唐氏综合征患儿出生,平个唐氏综合征患儿出生,平均均每每2020分钟就有分钟就有1 1例出生例出生,估计我国现有病人,估计我国现有病人6060万以万以上上(26,600 town syndromes occur in one year,one is born every 20(26,600 town syndromes occur in one year,one is born every 20 minutes,above 600,0000 in our country.)minutes,above 600,0000 in o
2、ur country.)发病率约占新生儿的发病率约占新生儿的1/7501/750,此征是引起先天智力,此征是引起先天智力障碍最常见的染色体病障碍最常见的染色体病(Incidence of 1 in 750 newborns,it is Incidence of 1 in 750 newborns,it is the most common chromosome disease causing congenital Intelligence the most common chromosome disease causing congenital Intelligence disturbance
3、)disturbance)本病与单基因遗传病的一个重要区别就是,它是偶发的,本病与单基因遗传病的一个重要区别就是,它是偶发的,每个孕妇都有生患儿的可能每个孕妇都有生患儿的可能(Different with single gene disease,it(Different with single gene disease,it is accidental and every is accidental and every pregnant woman has a chance to conceive this fetus.)我国每出生一例唐氏综合征患儿大约造成我国每出生一例唐氏综合征患儿大约造成
4、2525万元人万元人民币的社会经济负担。民币的社会经济负担。(250,000 RMB is needed to bring up one 250,000 RMB is needed to bring up one patient)patient)21-三体综合征 21-trisomy syndrome21-三体综合征一、遗传学基础细胞遗传学特征是21号染色体呈三体征发生原因:生殖细胞在减数分裂形成配子时21号染色体不分离。使胚胎细胞内存在3条21号染色体21-三体综合征 21-trisomy syndromen亲代生殖细胞减数分裂或受精卵早期卵裂时21号染色体不分离 病毒感染病毒感染 放射线、
5、同位素放射线、同位素 有毒物质(农药)有毒物质(农药)药物药物 母亲年龄母亲年龄21-三体综合征 21-trisomy syndrome21-三体综合征 21-trisomy syndrome21-三体综合征临床表现1n特殊面容 眼裂小、眼距宽、两眼裂外侧上斜 鼻梁低平 张口伸舌流涎临床表现2n体格发育迟缓 身材矮小 骨龄落后 坐、立、行均迟 出牙迟缓临床表现3、4n智能低下 IQ低 缺乏理解和思维能力n四肢关节柔软,易 弯曲。短而宽的手,第五指短而内弯、单一褶纹 Answer:Malfunction caused by developmental disorder of cerebrum i
6、ncludes cognition,memory,understanding,motion,words,comprehensive analysis,thought and imagination.))(Under age 18,IQM-2SD.After age 18,intelligence diminution is called dementia.)21-三体综合征21-三体综合征dermatoglyphcharacteristics21-三体综合征 21-trisomy syndrome dermatoglyphcharacteristics 21-三体综合征 21-trisomy
7、syndromedermatoglyphcharacteristics n伴发畸形n50伴先心病n消化道畸形:巨结肠、憩室n隐睾、小阴茎n女孩性发育迟缓21-三体综合征 21-trisomy syndromen急性淋巴细胞白血病发病率高(1/74)n免疫功能低下21-三体综合征 21-trisomy syndrome核型1 标准型(典型21三体型)95%47,XX(XY),+21 父母核型正常因亲代生殖细胞减数分裂时21号染色体不分离而造成核型2-1 易位型D/G易位46,XX(XY),-14,+t(14q21q)半数亲代为平衡易位携带者45,XX(XY),-14,-21+t(14q21q)核
8、型2-2G/G易位21/21易位46,XX(XY),-21,+t(21q21q)核型2-221/22易位46,XX(XY),-22,+t(21q22q)n5%亲代为平衡易位携带者n95%为突变核型3 嵌合型 46,XX(XY)/47,XX(XY)+21 临床表现差异较大,随正常细胞所占 百分比而异因受精卵早期卵裂时21号染色体不分离所造成n用荧光标记的21号染色体的相应片断DNA探针与患儿周围血中淋巴细胞进行杂交,呈现21号染色体的荧光信号三、实验室检查二、分子DNA探针21-三体综合征 21-trisomy syndrome 四、诊断n典型病例:特殊面容、智力与生长发育落后、皮纹特点,确诊需
9、染色体核型分染色体核型分析析n新生儿、不典型病例需染色体核型分析染色体核型分析21-三体综合征 21-trisomy syndrome 五、鉴别诊断n先天性甲状腺功能低下:粘液性水肿、头发干燥、便秘。T3 T4 TSHn脑性瘫痪:脑损伤病史、无特殊面容、皮纹改变,必要时做染色体核型分析21-三体综合征 21-trisomy syndrome21-三体综合征 21-trisomy syndromeantenatal diagnosis and to terminate pregnancy.)Different with Different with single gene disease,it
10、is single gene disease,it is accidental and every accidental and every pregnant woman has a chance to conceive this fetus.So every pregnant woman should have a risk assessment)南华大学附属怀化医院第八章第三节苯 丙 酮 尿 症phenylketonuria,PKU苯丙酮尿症是由于苯丙氨酸代谢途径中酶缺陷所致,是由于苯丙氨酸代谢途径中酶缺陷所致,因患儿尿液中排出大量苯丙氨酸等代谢产物而得名。因患儿尿液中排出大量苯丙氨酸等代
11、谢产物而得名。PKUPKU是氨是氨基酸代谢障碍中常见疾患,同时也是治疗最成功的疾患。基酸代谢障碍中常见疾患,同时也是治疗最成功的疾患。(PKU:enzymatic defection in Phenylalanine metabolism approach results in metabolite of phenylalanine discharging from urine.PKU is the most common and successfully curable disease)早期诊断、合理的饮食是挽救患儿的关键。早期诊断、合理的饮食是挽救患儿的关键。(Earlier period
12、 diagnosis and(Earlier period diagnosis and reasonable diet is the key)我国我国PKUPKU的发病率为的发病率为1 117000170001 160006000,全国每年约有,全国每年约有1500150020002000名患儿出生名患儿出生(Incidence:1/17000(Incidence:1/170001/6000,1500-1/6000,1500-2000 were born one year.)2000 were born one year.)苯丙酮尿症autosomal recessive lnheritanc
13、e.)phenylalanine 4 mhydroxylasel)Atypical PKU:lack of coenzyme)苯丙酮尿症苯丙酮尿症外观外观(appearance)others:vomiting,eczema,sweating,mouse smell urine)苯丙酮尿症eonatal screeningtest paper)analysis of the amino acid and Organic acid in the plasma and urine.)analysis:code gene locates in n典型患儿尿三氯化铁、2,4-二硝基苯肼试验阳性,但尿检易受其他因素影响,稳定性差,假阳性率高,易造成漏诊,只作为参考 苯丙酮尿症 phenylalanine diet and diet restriction continue to adolescence.)苯丙酮尿症 n避免近亲结婚 n开展新生儿筛查 n早期开始治疗 n已有PKU患儿的家庭再次生育时可进行产前诊断