Martorell Loreto, Cobo Ana Maria, Baiget Montserrat, Naudó Montserrat, Poza Juan José, Parra Juan
Molecular Genetics Section, Hospital Sant Joan de Déu, Barcelona, Spain.
Prenat Diagn. 2007 Jan;27(1):68-72. doi: 10.1002/pd.1627.
To analyse the results obtained from prenatal diagnoses in myotonic dystrophy type 1 (DM1) performed in our hospitals during the last 13 years.
Molecular analyses were conducted on chorionic villi or cultured amniotic fluid samples obtained for prenatal diagnosis of DM1. CTG expansion was analyzed by polymerase chain reaction (PCR) and Southern blot techniques.
From 154 prenatal diagnoses performed in 13 years, 51% were found to be healthy and 49% affected. Considering the 75 carriers of the mutation, in 65.3% of the cases, the mother was the transmitting parent versus 36.5% of fathers. From these female transmissions, 31/49 foetuses had expansion in the neonatal form range, namely, congenital myotonic dystrophy (CMD).
In our series, no significant deviation of the 50% expected frequency of transmission in autosomal dominant disorder was seen. We show that when the disease is transmitted by a male, the mean intergenerational variation is minimal (mean = 56 CTG, SD = 177 CTG). However, this does not occur in the affected mothers, where the mean intergenerational expansion is very high (mean = 948 CTG, SD = 815 CTG) and the difference is statistically significant (t-Student p < 0.0001). Our data have important implications for the genetic counselling of DM1 families.
分析过去13年在我院进行的1型强直性肌营养不良（DM1）产前诊断结果。
对用于DM1产前诊断的绒毛膜绒毛或培养的羊水样本进行分子分析。通过聚合酶链反应（PCR）和Southern印迹技术分析CTG扩增情况。
在13年进行的154例产前诊断中，51%被发现健康，49%患病。考虑到75名突变携带者，在65.3%的病例中，母亲是传递亲本，而父亲为36.5%。在这些女性传递中，49例胎儿中有31例在新生儿形式范围内扩增，即先天性强直性肌营养不良（CMD）。
在我们的系列研究中，未观察到常染色体显性疾病预期传递频率50%的显著偏差。我们发现，当疾病由男性传递时，平均代际变异最小（平均值 = 56 CTG，标准差 = 177 CTG）。然而，在患病母亲中并非如此，其平均代际扩增非常高（平均值 = 948 CTG，标准差 = 815 CTG），且差异具有统计学意义（t检验p < 0.0001）。我们的数据对DM1家族的遗传咨询具有重要意义。
