title: Would mean platelet volume/platelet count ratio be used as a novel formula to predict 22q11.2 deletion syndrome?
abstract: BACKGROUND
  The diagnosis of 22q11.2 deletion syndrome depends on a time-consuming and expensive method, fluorescence in situ hybridisation (FISH).
  
  
  OBJECTIVE
  We aimed to determine new parameters which can aid for in the diagnosis of 22q11.2 deletion syndrome.
  
  
  METHODS
  Twenty two patients with 22q11.2 or 10p13 deletion were evaluated retrospectively.
  
  
  RESULTS
  Facial-dysmorphism and mental-motor retardation were detected in 100% of patients. Mean platelet (PLT) counts were lower (224,980 versus 354,000, p = 0.001), mean PLT volume (MPV) (9.95 versus 7.07, p = 0.002), and MPV/PLTx105 ratios (5.36 versus 2.08, p < 0.001) were higher in patients with 22q11.2 deletion compared with the control group. Area under the receiver-operator characteristic (ROC) curve was 0.864, sensitivity was 84.6%, specificity was 90.9%, positive predictive value (PPV) was 91.7%, and negative predictive value (NPV) was 83.3% when MPV was 8.6. Area under ROC curve was 0.864, sensitivity was 76.9%, specificity was 90.1%, PPV was 90.1%, and NPV was 76.3% when PLT was 265,500. Area under ROC curve was 0.906, sensitivity was 84.6%, specificity was 100%, PPV was 100%, and NPV was 84.6% when MPV/PLTx105 was 3.3. Expression of PLT surface markers which were not in the GPIb-V-IX receptor complex (CD61, CD41a) increased as the surface area increased, but markers which were in a complex (CD42a, CD42b) did not change.
  
  
  CONCLUSIONS
  High MPV/PLT value can be a good predictor for the diagnosis of 22q11.2 deletion syndrome. We suggest that in patients with facial dysmorphism and retardation in neurodevelopmental milestones and if MPV≥8.6fl, MPV/PLTx105 ratio≥3.3 and PLT count ≤265,500/mm3, the patients should be tested by FISH analysis to confirm the 22q11.2 deletion. If there are no macrothrombocytes, the 10p13 deletion should be tested in suspected cases.
authors.affiliation: Baskent University Faculty of Medicine, Department of Pediatric Allergy and Immunology, Konya, Turkey.
authors.forename: Bahar
authors.initials: B
authors.lastname: Gokturk
authors.forename: Sukru Nail
authors.initials: SN
authors.lastname: Guner
authors.forename: Reyhan
authors.initials: R
authors.lastname: Kara
authors.forename: Mine
authors.initials: M
authors.lastname: Kirac
authors.forename: Sevgi
authors.initials: S
authors.lastname: Keles
authors.forename: Hasibe
authors.initials: H
authors.lastname: Artac
authors.forename: Ayse Gul
authors.initials: AG
authors.lastname: Zamani
authors.forename: Mahmut Selman
authors.initials: MS
authors.lastname: Yildirim
authors.forename: Ismail
authors.initials: I
authors.lastname: Reisli
mesh_terms: D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D001792:Blood Platelets; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D004062:DiGeorge Syndrome / Q000097:blood / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D008607:Intellectual Disability / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D008297:Male; D063847:Mean Platelet Volume; D009043:Motor Activity; D010641:Phenotype; D010976:Platelet Count; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult