Recombinant 4 syndrome due to an unbalanced pericentric inversion of chromosome 4.

An informative patient with a MCA/MR syndrome consisting of developmental delay, prenatal onset growth delay, microcephaly, distinctive face, iris coloboma, and a congenital heart defect was found, on chromosome analysis, to have the following complement: 46,XY,rec(4) dup(4p) inv(4)(p14q35.1) mat. He has a partial 4p trisomy/distal 4q deletion due to an unbalanced pericentric inversion inherited from his mother. Dup (4p) trisomy was originally described by Wilson et al. [1970: Am J Hum Genet 22:679-690] in a similar case with the same chromosome 4 inversion. To date, at least 85 cases of dup (4p) syndrome have been published, mostly due to unbalanced translocations. Recent articles suggest that the phenotype is hard to recognize clinically due to the lack of specificity of findings. In contrast, 4p trisomy due to an unbalanced pericentric inversion of chromosome 4(p14q35), i.e., the recombinant 4 syndrome observed in our patient, appears to be a discrete entity with relatively consistent features. In total there are four other kindreds described in the literature with this inversion, and the phenotype seems recognizable. Thus, we suggest that recombinant 4 syndrome is a discrete entity among 4p trisomy patients.