Identification of a cryptic t(5;11) by whole chromosome painting and FISH with subtelomeric probes. (A) The whole chromosome 5 paint highlights the normal chromosome 5 homologue, the del(5q) (arrow), and the tip of an apparently normal chromosome 11 (arrowhead) in a metaphase from patient no. 3. Subtelomeric probes for 5p, 5q (B) and 11p, 11q (C) confirm the t(5;11) in metaphases from patient no. 2. In each case, the p arm subtelomeric probe is detected in Texas Red (red fluorescent signal) and the q arm subtelomeric probe is detected in fluorescein (green fluorescent signal). In both cases, the normal chromosome homologue has fluorescent signal corresponding to both the p and q arm subtelomeric probes. In (B), the del(5q) has only the p arm signal present (arrow), with the 5q subtelomeric probe present on the the short arm of the der(11) (arrowhead). Similarly, in (C), the der(11) (arrowhead) shows only the q arm signal, with the 11p subtelomeric probe sequences present on the del(5q) (arrow).