Özlem ANLAŞ, G. Ozan ÇETİN, Kanay YARARBAŞ, Füsun DÜZCAN, Cavidan Nur Semerci GÜNDÜZ, Akif AYAZ, Gülseren BAĞCI

A case of recombinant chromosome 4: further delineation of the clinical features

Recombinant chromosome 4 is a very rare chromosomal aberration with eighteen cases reported in the literature up to date. Here we report a five years old male patient with de novo rec(4) dup(4p) del(4q). The physical examination findings were as follows: caput quadratum, flat occiput, low frontal hairline, hypertelorism, ptosis, blepharophimosis, high arched eyebrows, flat nasal root with anteverted nostrils and short nose, long and smooth philtrum, thin upper lip with triangular mouth, microretrognathia, high arched palate, dental anomalies, large low-set ears, short neck, broad chest with widely spaced nipples, micropenis, cryptorchidism. Conventional cytogenetic analysis revealed the karyotype as 46,XY,rec(4)dup(4p14p16.3)del(4q34.3q35). Flourescence insitu hybridization (FISH) analysis with sub-telomeric probes for 4p and 4q showed duplication of 4p and deletion of 4q in recombinant chromosome 4. His parents’ chromosomal analysis and sub-telomeric FISH analysis were both normal. The patient’s final karyotype was reported as 46,XY,rec(4)dup(4p16.3p14)del(4q34.4q35).arr[h g19]4p16.3p14(68,345-36,018)x3,4q34.3q35(177,676,319-190,957,460)x1 detected by Microarray. According the literature all cases with recombinant chromosome 4 have similar clinical findings. Except for our case only one case in the literature has been reported to be de novo. In conclusion, we reported a very rare case of recombinant chromosome 4, which has the largest deletion and duplication in the literature. Further cases with similar findings would help the delineation of the findings associated with this chromosomal abnormality.

Rekombinant kromozom 4, literatürde bugüne kadar bildirilen 18 vakayla birlikte ender görülen bir kromozomal anormalidir. Bu yazıda de novo rec (4)dup(4p)del(4q) karyotipine sahip 5 yaşında bir erkek hastayı bildirdik. Hastanın fizik muayenesinde kaput kuadratum, yassı oksiput, düşük frontal saç çizgisi, hipertelorizm, pitozis, blefarofimozis, yüksek kemerli kaşlar, antevert burun delikleri ile düz burun kökü, kısa burun, uzun ve pürüzsüz filtrum, üçgen ince üst dudak, mikroretrognati, yüksek kemerli damak, diş anomalileri, geniş, düşük kulaklar, kısa boyun, geniş aralıklı meme uçları, mikropenis, kriptorşidizm saptanmıştır. Konvansiyonel sitogenetik analiz sonucunda karyotipin 46,XY,rec(4)dup(4p14p16.3)del(4q34.3q35) karyotipi saptanmıştır. 4p ve 4q için subtelomerik problarla yapılan floresan in-situ hibridizasyon (FISH) analizi, rekombinant kromozom 4'te 4p'nin duplikasyonunu ve 4q'nun delesyonunu göstermiştir. Yapılan microarray analizi sonrası hastanın son karyotipi 46,XY, rec (4) dup (4p16.3p14) del (4q34.4q35) .arr [hg19] 4p16.3p14 (68.345-36.018) x3,4q34.3q35 (177,676,319-190,957,460) olarak rapor edilmiştir. Literatüre göre rekombinant kromozom 4 olan tüm olgular benzer klinik bulgulara sahiptir. Bizim olgumuz dışında literatürde sadece bir olgunun de novo olduğu bildirilmiştir. Sonuç olarak, bu yazıda nadir bir rekombinant kromozom 4 olgusu bildirilmiştir. Benzer bulgulara sahip bildirilecek diğer vakalar, nadir görülen bu rekombinasyonun daha iyi tanımlanmasına yardımcı olacaktır.

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