A PARTIAL TRISOMY 9 CASE WITH DICENTRIC CHROMOSOME DUE TO THE ADJACENT-2 SEGREGATION OF MATERNAL RECIPROCAL TRANSLOCATION

Yıl 2022, Cilt: 85 Sayı: 2, 279 - 284, 24.03.2022

Ezgi Urtekin Gülsüm Kayhan Elvin Kazancıoğlu Meral Yirmibeş Karaoğuz

https://doi.org/10.26650/IUITFD.1038997

Öz

Duplication of the short arm (p) of chromosome (Chr.) 9 is a frequently seen abnormality while duplication of both p and long arm (q) is a rare chromosomal rearrangement derived mostly from parental translocations or inversions. The unbalanced products of the translocations are mostly derived from the 2:2 segregation of adjacent 1division while the ones due the adjacent two patterns are rare. Here, a dysmorphic infant with a pure duplication of 9pter to 9q22.31 is reported due to the product of the adjacent-2 segregation of maternal reciprocal translocation between the 9q22.31 and 22p11.1. The affected infant had two normal and one derivative/dicentric Chr.9 (carrying the centromere regions of both Chr.9 and Chr.22) with one normal Chr.22. These results were confirmed by the fluorescence in situ hybridization technique. Array-comparative genomic hybridization confirmed the breakpoints precisely and revealed a 61.75 megabases duplication of Chr.9 consisting of many genes such as BICD2, NTRK2, HNRNPK, and SMARCA2, which are mostly related to developmental delay and growth retardation. Additionally, the infant had ear abnormalities, microcephaly, and extremity abnormalities, which were the other findings of trisomy 9. In sum, the case has presented as a rare example of adjacent 2 division of 2:2 segregation and a pure partial trisomy of 9pter to 9q22.31.

Anahtar Kelimeler

Partial trisomy 9, reciprocal translocation, adjacent-2 segregation, dicentric chromosome, chromosomal rearrangement, growth retardation, fluorescence in situ hybridization, array- comparative genomic hybridization

MATERNAL RESİPROKAL TRANSLOKASYONUN ADJACENT-2 SEGREGASYONUNA BAĞLI OLUŞAN DİSENTRİK KISMİ TRİZOMİ 9 OLGUSU

Öz

Kromozom (Chr.) 9’un kısa koluna (p) ait duplikasyon sık görülmekle birlikte daha çok ailesel translokasyonlara ve inversiyonlara bağlı oluşan, hem kısa hem de uzun kolun (q) duplikasyonu nadir görülen bir kromozomal yeniden düzenlenmedir. Ailesel translokasyonlara bağlı oluşan dengesiz gebelik ürünleri daha çok 2:2 segregasyonun adjacent-1 aktarımı ile oluşmakta iken, adjacent 2 aktarımı nadir bir durumdur. Burada, annenin 9q22.31 ve 22p11.1 bölgeleri arasındaki resiprokal translokasyonuna bağlı 9pter ile 9q22.31 bölgeleri arasında duplikasyonu olan dismorfik bir çocuk sunulmaktadır. Etkilenmiş çocuk iki normal Chr.9, bir derivatif/disentrik Chr.9 (hem Chr.9, hem de Chr.22’nin sentromerini taşıyan), bir tane de normal Chr.22’ye sahiptir. Tüm bu sonuçları floresan insitu hibridizasyon tekniği teyit etmiştir. Kırık bölgelerini doğru olarak belirleyen array-karşılaştırmalı genomik hibridizasyon tekniği BICD2, NTRK2, HNRNPK ve SMARCA2 gibi büyüme gelişme geriliğine eşlik eden genleri de kapsayan kromozom 9’a ait 61,75 megabazlık duplikasyonu ortaya çıkarmıştır. Ek olarak mikrosefali ve ekstremite anomalileri gibi trizomi 9’a eşlik eden diğer bulgular da olguda bulunmaktadır. Özetle bu olgu, adjacent 2 tipi segregasyonun ve sadece 9pter-9q22.31 bölgelerini kapsayan kısmi trizomi 9’un nadir bir örneği olarak sunulmaktadır.

Anahtar Kelimeler

Kısmi trizomi 9, resiprokal translokasyon, büyüme geriliği, floresan insitu hibridizasyon, array-karşılaştırmalı genomik hibridizasyon, adjacent-2 segregasyonu, disentrik kromozom, kromozomal yeniden düzenlenme

Kaynakça

• 1. National organization for rare disorders (NORD). Rare Disease Database. https://rarediseases.org/rare-diseases/ chromosome-9-trisomy-9p-multiple-variants (accessed January, 2022).
• 2. Arnold GL, Kirby RS, Stern TP, Sawyer JR. Trisomy 9: Review and report of two new cases. Am J Med Genet 1995;56(3):252-7. [CrossRef]
• 3. Sutherland GR, Carter RF, Morris LL. Partial and complete trisomy 9: Delineation of a trisomy 9 syndrome. Hum Genet 1976;32(2):133-40. [CrossRef]
• 4. Seabright M. A rapid banding technique for human chromosomes. Lancet 1971;2(7731):971-2. [CrossRef]
• 5. Feingold M, Atkins L. A case of trisomy 9. J Med Genet 1973;10(2):184-7. [CrossRef]
• 6. Dhangar S, Korgaonkar S, Vundinti BR. Partial trisomy 9 (9pter->9q22.1) and partial monosomy 14 (14pter- >14q11.2) due to paternal translocation t(9;14)(q22.1;q11.2) in a case of dysmorphic features. Intractable Rare Dis Res 2019;8(1):72-7. [CrossRef]
• 7. von Kaisenberg CS, Caliebe A, Krams M, Hackelöer BJ, Jonat W. Absence of 9q22-9qter in trisomy 9 does not prevent a Dandy-Walker phenotype. Am J Med Genet 2000;95(5):425-8. [CrossRef]
• 8. López-Félix J, Flores-Gallegos L, Garduño-Zarazúa L, Leis- Márquez T, Juárez-García L, Meléndez- Hernández R, et al. Partial trisomy 9: Prenatal diagnosis and recurrence within same family. Clin Case Rep 2017;5(6):986-92. [CrossRef]
• 9. Metzke-Heidemann S, Kuhling-von Kaisenberg H, Caliebe A, Janssen D, Jonat W, Grote W, et al. Phenotypical variation in cousins with the identical partial trisomy 9 (pter-q22.2) and 7 (q35-qter) at 16 and 23 weeks gestation. Am J Med Genet 2004;126A(2):197-203. [CrossRef]
• 10. Stimpson KM, Matheny JE, Sullivan BA. Dicentric chromosomes: unique models to study centromere function and inactivation. Chromosome Res 2012;20(5):595- 605. [CrossRef]
• 11. Meiser B, Irle J, Lobb E, Barlow-Steward K. Assessment of the content and process of genetic counseling: A critical review of empirical studies. J Genet Couns 2008;17(5):434- 51. [CrossRef]
• 12. Temtamy SA, Kamel AK, Ismail S, Helmy NA, Aglan MS, El Gammal M, et al. Phenotypic and cytogenetic spectrum of 9p trisomy. Genet Couns 2007;18(1):29-48.
• 13. Lindgren V, Rosinsky B, Chin J, Berry-Kravis E. Two patients with overlapping de novo duplications of the long arm of chromosome 9, including one case with Di George sequence. Am J Med Genet 1994;49(1):67-73. [CrossRef]
• 14. Littooij AS, Hochstenbach R, Sinke RJ, van Tintelen P, Giltay JC. Two cases with partial trisomy 9p: molecular cytogenetic characterization and clinical follow-up. Am J Med Genet 2002;109(2):125-32. [CrossRef]
• 15. Sato A, Suzuki T, Ikeno M, Takeda J, Yamamoto Y, Shinohara M, et al. Pure 9p duplication syndrome with aplasia of the middle phalanges of the fifth fingers. Eur J Med Genet 2020;63(10):104005. [CrossRef]