1. ¹Laboratorio di Citogenetica, Istituto Auxologico Italiano, Milan, Italy
2. ²Dipartimento di Biologia e Genetica, Università degli Studi, Milan, Italy
3. ³Struttura Semplice di Citogenetica, Clinica Ostetrica e Ginecologica, Presidio Ospedaliero M Melloni, Milan, Italy
4. ⁴Dipartimento di Scienze Pediatriche, Policlinico Universitario, Messina, Italy

Correspondence: Dr D Giardino, Laboratorio di Citogenetica Medica, Istituto Auxologico Italiano, Via Ariosto 13, Milan 20145, Italy. Tel: +39 02 619112012; Fax: +39 02 619112464; E-mail: giardino@auxologico.it

Received 17 June 2003; Revised 8 November 2003; Accepted 20 November 2003; Published online 31 March 2004.

Abstract

A rec(5)dup(5)(q23.2q31.3) inherited from a maternal ins(5)(p13.1q23.2q31.3) was detected in a 4-month-old male child who showed hypotonia, microcephaly, cardiac defects, pulmonary hypoplasia and stenosis, bilateral hydronephrosis, hydrocele, testicular hypoplasia and phimosis. Dysmorphisms were also observed. We compare the clinical characteristics of our patient with those of the previously reported dup5q cases in an attempt to define the phenotype–karyotype correlation. The maternal insertion responsible for the duplicated 5q23.2–31.3 region in the child was characterized in detail by FISH analysis, which identified a complex rearrangement involving four breakpoints (bkp's): a 5q segment excised following breakage at 5q23.2 and 5q31.3 became inverted and inserted at 5p13.1, probably coincidentally with an internal breakage at 5q23.3 causing a 180° rotation of the two subsegments. The mother's karyotype was consequently defined as 46,XX, ins(5)(pter p13.1q23.3 q23.2q31.3 q23.3p13.1 q23.2q31.3 qter). There are clusters of Alu sequences in the genomic clones spanning all the four bkp's, suggesting their possible involvement in the rearrangement. No clinical phenotype was associated with this balanced rearrangement in the mother and a number of other carriers in the same family.