• Journal of Genetic Medicine
• /
• 제15권1호
• /
• pp.8-12
• /
• 2018

Purpose: This study aimed to investigate fetal ultrasonographic findings in cases of prenatally diagnosed de novo balanced translocations and the role of fetal ultrasound in prenatal genetic counseling. Materials and Methods: We collected cases with de novo balanced translocations that were confirmed in chorionic villus sampling, amniocentesis, and cordocentesis between 1995 and 2016. A detailed, high-resolution ultrasonography was performed for prediction of prognosis. Chromosomes from the parents of affected fetuses were also analyzed to determine whether the balanced translocations were de novo or inherited. Results: Among 32,070 cases with prenatal cytogenetic analysis, 27 cases (1/1,188 incidence) with de novo balanced translocations were identified. Fourteen cases (51.9%) showed abnormal findings, and the frequency of major structural anomalies was 11.1%. Excluding the major structural anomalies, all mothers who continued pregnancies delivered healthy babies. Conclusion: Results of a detailed, high-resolution ultrasound examination are very important in genetic counseling for prenatally diagnosed de novo balanced translocations.

• Journal of Genetic Medicine
• /
• 제8권2호
• /
• pp.135-138
• /
• 2011

초산인 35세 산모가 고령 임신과 모체혈액선별검사 고위험군을 주소로 양수천자를 실시한 결과 8번 염색체의 단완에 위성체가 붙어 있는 것이 발견되었다. 부모 염색체 검사 결과 모두 정상으로 확인되어 태아에게서 관찰된 8ps현상은 de novo로 판단된다. FISH 검사로 좀 더 자세히 분석한 결과, 8번 염색체와 22번 염색체 사이에 미세한 전좌가 관찰되었다. 태아의 염색체 8번과 22번 사이의 de novo 전좌를 갖고 있었지만 절단 부위가 DNA의 단순 반복 부위이므로 표현형에 영향을 미칠 가능성은 높지 않을 것으로 추측되었고, 임신 기간 동안 초음파상 이상 소견은 관찰되지 않았다. 유전 상담을 통해 8번 염색체 단완의 미세 결실 가능성이 설명되었고, 부모의 결정에 따라 추가실험 없이 임신은 유지되었다. 그리고 38주에 정상 표현형의 남아가 분만되었다. 본 증례는 산전 진단에서 세포유전학적 검사로 8번 염색체 단완의 위성체만이 발견되었으나, 추가의 분자세포유전학적 진단으로 8번과 22번 염색체 단완 사이의 미세한 전좌를 확인하였다. 이처럼보다 정확하고 자세한 분자세포 유전학적 분석들이 산전 진단에서는 필요함을 시사한 사례였다.

• Clinical and Experimental Pediatrics
• /
• 제54권6호
• /
• pp.267-271
• /
• 2011

Distal duplication, or trisomy 15q, is an extremely rare chromosomal disorder characterized by prenatal and postnatal overgrowth, mental retardation, and craniofacial malformations. Additional abnormalities typically include an unusually short neck, malformations of the fingers and toes, scoliosis and skeletal malformations, genital abnormalities, particularly in affected males, and, in some cases, cardiac defects. The range and severity of symptoms and physical findings may vary from case to case, depending upon the length and location of the duplicated portion of chromosome 15q. Most reported cases of duplication of the long arm of chromosome 15 frequently have more than one segmental imbalance resulting from unbalanced translocations involving chromosome 15 and deletions in another chromosome, as well as other structural chromosomal abnormalities. We report a female newborn with a de novo duplication, 15q24- q26.3, showing intrauterine overgrowth, a narrow asymmetric face with down-slanting palpebral fissures, a large, prominent nose, and micrognathia, arachnodactyly, camptodactyly, congenital heart disease, hydronephrosis, and hydroureter. Chromosomal analysis showed a 46,XX,inv(9)(p12q13),dup(15)(q24q26.3). Array comparative genomic hybridization analysis revealed a gain of 42 clones on 15q24-q26.3. This case represents the only reported patient with a de novo 15q24-q26.3 duplication that did not result from an unbalanced translocation and did not have a concomitant monosomic component in Korea.

• Journal of Genetic Medicine
• /
• 제11권1호
• /
• pp.16-21
• /
• 2014

A 31-year-old woman, who was pregnant with twins, underwent chorionic villus sampling because of increased nuchal translucency in one of the fetuses. Cytogenetic analysis showed a normal karyotype in the fetus with increased nuchal translucency. However, the other fetus, with normal nuchal translucency, had a derivative X chromosome (der(X)). For further analysis, fluorescence in situ hybridization (FISH) and additional molecular studies including fragile X analysis were performed. FISH analysis confirmed that the Y chromosome was the origin of extra segment of the der(X). The X-chromosome breakpoint was determined to be at Xq27 by FMR1 CGG repeat analysis, and the Y-chromosome breakpoint was determined to be at Yq11.23 by the Y chromosome microdeletion study. To predict the fetal outcome, the X-inactivation pattern was examined, and it revealed non-random X inactivation of the der(X). To the best of our knowledge, the identification of an unbalanced Xq;Yq translocation at prenatal diagnosis has never been reported. This study was performed to identify precise breakpoints and the X-inactivation pattern as well as to provide the parents with appropriate genetic counseling.