Author/Editor		Erjavec-Škerget, Alenka; Zagradišnik, Boris; Kokalj-Vokač, Nadja
Title		Subtelomerne kromosomske preureditve - eden od vzrokov za idiopatsko mentalno retardacijo
Translated title		Subtelomeric chromosomal abberations - one of the reasons for idiopathic mental retardation
Type		članek
Source		Zdrav Vestn
Vol. and No.		Letnik 72, št. 6
Publication year		2003
Volume		str. 359-65
Language		slo
Abstract		Background. Cryptic subtelomeric chromosome anomalies have been recognised as a significant cause of idiopathic mental retardation (IMR) and/or dysmorphology. This study presents an innovative simmultane fluorescence in situ hybridisation (FISH) technique for detection of subtelomeric rearrangements that was introduced to the laboratory. It was found out that this method is a very useful diagnostic tool with application in the field of idiopathic mental retardation, for detection of congenital abnormalities and in resolving complex karyotypes. This study was done on 56 mentally retarded and/or dysmorphic children from the northeastern part of Slovenia. Methods. All patients were karyotyped using 5 ml peripheral blood samples. FISH testing using the Cytocell Multiprobe T-System and some locus specific DNA probes was performed for detection of subtelomeric chromosomal rearrangements. Results. Subtelomeric alterations were detected in 5.4% patients. Clinical significant "de novo" subtelomeric aberrations were detected in 3.6% of patients while deletion of the 2q subtelomeric region del(2)(qtel) appeared to be a common variant and inheritive in both of our cases. Two subtelomeric aberrations such as del(X)(ptel) and monosomy of (13)(qtel), and partial trisomy of chromosome 10 in (10)(qtel) region were found among the patients during this screening. Conclusions. Furthermore, fluorescence in situ hybridisation (FISH) technique using the multiprobe subtelomeric DNA system proved to be a useful diagnostic tool for screening the patients with or without dysmorphic feature and normal karyotype.
Summary		Izhodišča. Kromosomske napake so lahko eden od vzrokov za idiopatsko mentalno retardacijo (IMR) in dismorfologijo. V prispevku poročamo o vpeljavi simultane metode jluorescenčne hibridizacije "in situ" (FISH)za odkrivanjes ubtelomernih kromosomskih preureditev. Ugotavljamo, da je metoda lahko uporabna za rutinsko citogenetsk"o diagnostiko IMR, kongenitalnih anomalij in razreševanje kompleksnejših kariotipov. Pilotsko študijo smo izvedli pri 56 bolnikih, otrocih izseverovzhodne Slovenije, ki so bili napoteni v citogenetski laboratorij z diagnozo mentalne retardacije in/ali displastičnih znakov. Metode. Vsem bolnikom smo odvzeli 5 mlperiferne krvi in jih kariotipizirali. Za odkrivanje kromosomskih sprememb v terminalnih regijah kromosomov smo uporabili metodo FISHz uporabo kompleta Multiprobe T-System (Cytocell) ter posamezne lokusno specifične DNK sonde. Rezultati. Subtelomerne spremembe smo našli pri 5,4% bolnikov Od tega so pri 3,6% bolnikov subtelomerne aberacije nastale "de novo". 2q subtelomerna delecija: del(2)(qtel), ki smo jo našli pri dveh bolnikih, pa se je izkazala kot dedovani polimorfizem. Subtelomerne aberacije smo potrdili pri enem pacientu z delecijo terminalnega dela kratkega kraka kromosoma X: del(X)(ptel) in pri drugem z delecijo terminalnega dela dolgega kraka 13: del(13)(qtel) in parcialno trisomijo dela dolgega kraka kromosoma 10. Zaključki. Sprikazano študijo ugotavljamo, da je metoda FISH zmultiplimi subtelomernimi DNK-sondami uporabno diagnostično orodje za odkrivanje enega od vzrokov IMR pri bolnikih z displastičnimi znaki ali brez teh znakov s sicer normalnim kariotipom.
Descriptors		MENTAL RETARDATION CHROMOSOME ABERRATIONS TELOMERE IN SITU HYBRIDIZATION, FLUORESCENCE DNA PROBES KARYOTYPING