We hypothesize that haploinsufficiency of the 15q26 genomic region distal to IGF1R gene might be related to growth disturbance; however, presence of the ring chromosome 15 itself could also be responsible for the growth delay.
In all three patients, the insulin-like growth factor I receptor gene (IGF1R) gene was deleted supporting the association between IGF1R and growth retardation seen in ring chromosome 15 syndrome.
The correlation between IGF1R gene dosage and growth retardation demonstrated here in our ring chromosome 15 patients suggests a possible role for heterozygous IGF1R gene mutations or deletions in other cases of unexplained growth failure.