Interstitial deletion of bands 11q21-->22.3 in a three-year-old girl defined using fluorescence in situ hybridization on metaphase chromosomes.

A 3-year-old girl has a de novo deletion of 11q21-22.3. The patient was studied because of minor anomalies, disproportionate short stature, and developmental delay. The deletion was first detected by conventional cytogenetic analysis and defined further by using chromosome 11-specific YAC clones by fluorescent in situ hybridization (FISH) on metaphase chromosomes. Three YAC clones, 11H7, 4A5, and IH4, were lacking from one of the patient's chromosome 11. Trigonocepahly, hypertelorism, apparently low-set ears, mild renal abnormality, and delay in speech development found in our patient are similar findings in other published interstitial deletion cases. Our study shows that a molecular cytogenetic approach is useful in defining the specific location and the extent of an interstitial deletion in cytogenetically difficult areas such as 11q.