MULTIPLEX PCR OF 3 DINUCLEOTIDE REPEATS IN THE PRADER-WILLI-ANGELMAN CRITICAL REGION (15Q11-Q13) - MOLECULAR DIAGNOSIS AND MECHANISM OF UNIPARENTAL DISOMY
MULTIPLEX PCR OF 3 DINUCLEOTIDE REPEATS IN THE PRADER-WILLI-ANGELMAN CRITICAL REGION (15Q11-Q13) - MOLECULAR DIAGNOSIS AND MECHANISM OF UNIPARENTAL DISOMY
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DOI：
10.1093/hmg/2.2.143
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发表时间：
1993-02-01
影响因子：
3.5
通讯作者：
LEDBETTER, DH
中科院分区：
文献类型：
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作者：
MUTIRANGURA, A;GREENBERG, F;LEDBETTER, DH
Prader-Willi综合征（PWS）和Angelman综合征（AS）是由父亲（PWS）或母亲（AS）对15号染色体的缺失或单亲二体性（UPD）引起的不同的精神发育迟滞疾病。为了进一步研究这些疾病的分子机制，并提高分子诊断方法，我们已经分离出三个二核苷酸重复标记的PWS/AS关键区域。利用PCR方法从酵母人工染色体（YAC）克隆中直接分离CA重复序列标记，其中YAC克隆用探针IR 4 -3R（D15 S11）、LS 6 -1（D15 S113）和GABA（A）受体B3（GABRB 3）鉴定。通过多重PCR技术筛选出3个等位基因数为6-11个、杂合度为73-83%的标记。基因-着丝粒定位在一组已知减数分裂起源的卵巢畸胎瘤上进行，并显示最近的标记，IR 4 -3R，距离15号染色体的着丝粒13 cM（95%置信限：7-19 cM）。对20例PWS和9例AS患者进行了分子诊断研究。在17例缺失患者中，确定了缺失的父母来源。10例PWS患者被证明具有母体异二体性。由于这些标记距离着丝粒只有13 cM，异二体性表明母体减数分裂I不分离参与了UPD的起源。与此相反，两个父亲的二体性的情况下，显示等位基因的所有标记测试沿着长度的15号染色体。这表明一个父亲减数分裂II不分离事件（没有交换），或更可能的是，单体概念（由于母亲不分离），随后染色体复制。后一种机制表明PWS和AS中的UPD可能是母体不分离事件的相互产物。
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct mental retardation disorders caused by a deficiency of paternal (PWS) or maternal (AS) contributions for chromosome 15 by either deletion or uniparental disomy (UPD). To further study the molecular mechanisms involved in these disorders and to improve molecular diagnostic methods, we have isolated three dinucleotide repeat markers in the PWS/AS critical region. An Alu-CA PCR method was used to isolate CA-repeat markers directly from yeast artificial chromosome (YAC) clones identified by probes IR4-3R (D15S11), LS6-1 (D15S113), and GABA(A) receptor B3 (GABRB3). Three markers with 6-11 alleles and 73-83% heterozygosities were identified and analyzed by multiplex PCR. Gene-centromere mapping was performed on a panel of ovarian teratomas of known meiotic origin, and showed the most proximal marker, IR4-3R, to be 13 cM (95% confidence limits: 7-19 cM) from the centromere of chromosome 15. Molecular diagnostic studies were performed on 20 PWS and 9 AS patients. In 17 patients with deletions, the parental origin of deletion was determined. Ten PWS patients were shown to have maternal heterodisomy. Since these markers are only 13 cM from the centromere, heterodisomy indicates that maternal meiosis I nondisjunction is involved in the origin of UPD. In contrast, two paternal disomy cases of AS showed isodisomy for all markers tested along the length of chromosome 15. This suggests a paternal meiosis II nondisjunction event (without crossing over) or, more likely, monosomic conception (due to maternal nondisjunction) followed by chromosome duplication. This latter mechanism would indicate that UPD in PWS and AS may initiate as reciprocal products of maternal nondisjunction events.