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Phelan-McDermid Syndrome, deletion 22q13 by FISH

Test Code


Test Synonyms

N25/ARSA, del(22)(q13.3)


Fluorescence in situ Hybridization (FISH)
*performed by affiliate laboratory

Turnaround Time

7-10 days

Specimen Requirements

5.0 mL whole blood, sodium heparin

Specimen Stability
Peripheral blood stable at 4-25°C for 72 hours
Storage & Handling

Protect from extreme temperature. Ship on Saturday for Monday delivery only if sample is Ship with cool pack (refrigerated). protected from extreme temperature.

Causes for Rejection

Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells

Reference Range

See report

It is recommended that all FISH studies be done in conjunction with routine cytogenetic studies. If the FISH result is normal, a chromosome analysis allows identification of more complex abnormalities.


Some symptoms include neonatal hypotonia, absent/delayed speech, moderate/profound developmental delay as well as minor dysmorphic features, including dolicocephaly, periorbital fullness, long eyelashes, prominent/full brow, large fleshy hands, dysplastic toenail. Behavioral featues include decreased perception of pain, obsessive chewing or mouthing, autism or autistic-like affect.

  1. Moessner R et al. (2007). Contribution of SHANK3 mutations to autism spectrum disorders. Am J Hum Genet. 81:1289-1297.
  2. Phelan MC et al. (2005). Deletion 22q13 syndrome (Phelan-McDermid syndrome). Management of Genetic Syndromes. 2nd ed. SB Cassidy and JE Allanson. Wiley-Liss. 171-181.
  3. Wilson HL et al. (2003). Molecular characterisation of the 22q13 deletion syndrome supports the role of haploinsufficiency of SHANK3/PROSAP2 in the major neurological symptoms. J Med Genet. 40:575.