22q11.2 deletion detected by in situ hybridization in Mexican patients with velocardiofacial syndrome-like features.
Abstract
Introduction: Deletion 22q11.2 occurs in 1:4,000-1:6,000 live births while 10p13p14 deletion is found in 1:200,000 newborns. Both deletions have similar clinical features such as congenital heart disease and immunological anomalies.
Objective: We looked for a 22q11.2 deletion in Mexican patients with craniofacial dysmorphisms suggestive of DiGeorge or velocardiofacial syndromes and at least one major phenotypic feature (cardiac anomaly, immune deficiency, palatal defects or development delay).
Methods: A prospective study of 39 patients recruited in 2012-2015 at the Instituto Mexicano del Seguro Social at Guadalajara, Mexico. The patients with velocardiofacial syndrome-like features or a confirmed tetralogy of Fallot (TOF) or complex cardiopathy were studied by G-banding and fluorescence in situ hybridization (FISH) with a dual TUPLE1(HIRA)/ARSA or TUPLE1(22q11)/22q13(SHANK3) probe, six patients without the 22q11.2 deletion (arbitrarily selected) were tested with the dual DiGeorge II (10p14)/D10Z1 probe.
Results: Twenty-two patients (7 males and 15 females) had the 22q11.2 deletion and 17/39 did not have it; no patient had a 10p loss. Among the 22 deleted patients, 19 had congenital heart disease (mostly TOF). Twelve patients without deletion had heart defects such as TOF (4/12), isolate ventricular septal defect (2/12) or other disorders (6/12).
Conclusion: In our small sample about ~56% of the patients, regardless of the clinical diagnosis, had the expected 22q11.2 deletion. We remark the importance of early cytogenetic diagnosis in order to achieve a proper integral management of the patients and their families.
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Keywords
- 22q11.2 deletion
- DiGeorge syndrome
- Tetralogy of Fallot
- congenital heart defects
- craniofacial abnormalities
- velocardiofacial syndrome
![A partial metaphase after FISH with a dual TUPLE1 red spectrum /ARSA green spectrum probe (Vysis®). The normal 22 chromosome had red and green signals meanwhile the deletion 22q11.2 chromosome lacked the red signal and had only the green one.](https://colombiamedica.univalle.edu.co/colombiamedica311/public/journals/1/article_3912_cover_en_US.jpg)
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