Metaphase FISH Examples


DiGeorge Probe

This is an example of a metaphase cell that has been hybridized with the probe for DiGeorge/Velo-Cardio-Facial/CATCH 22/Shprintzen Syndrome which is caused by a microdeletion on chromosome 22. The probe in this particular case is a dual-color mixture of two seperate probes for chromosome 22. The green signal is an internal control and is located at 22q13. It allows for quick identification of both #22 chromosomes. The red signal is located at the DiGeorge region at 22q11.2. Since both 22's have the red signal in this cell there is not a microdeletion within the DiGeorge region and this individual would not have DiGeorge Syndrome.


Chromosome 4 Paint Probe

This metaphase has been hybridized with a "painting" probe for chromosome 4 which causes the entire chromosome to fluoresce. One chromosome 4 from this individual was abnormal but it was difficult to determine from routine Cytogenetics if it had a small terminal deletion at 4q or was the result of a more complex rearrangement. Since both 4's are fluorescent along their entire length and no fluorescent material is present on any other chromosome, this suggests that the abnormality is a small terminal deletion. The metaphase below is from the same individual and further confirms this diagnosis.

Chromosome 4qter Probe

This metaphase from the same individual as the cell above has been hybridized with a probe for the terminal part of chromosome 4q. Since there is only one green signal this confirms that one chromosome 4 is missing material from the terminal end of 4q. This case is a good example of how routine Cytogenetics and FISH can be used together to accurately diagnose subtle chromosome abnormalities.


Steroid Sulfatase Probe

This is an example of a metaphase cell that has been hybridized with the probe for Steroid Sulfatase Deficiency which is caused by a microdeletion on the X chromosome. The probe in this particular case is a mixture of two seperate probes for the X chromosome, both red in color. The "X cen" probe signal is an internal control and is located at the X centromere. It allows for quick identification of the X chromosome(s). The "Xp22.3" probe signal is located at the Steroid Sulfatase region at Xp22.3. Since there are two X chromosomes and only one has the Steroid Sulfatase gene signal, this individual is a female carrier for Steroid Sulfatase Deficiency.




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