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22q11.2 deletion detected by in situ hybridization in 22/39 Mexican patients with velocardiofacial syndrome-like features
Ramírez-Velazco, Azubel; Rivera, Horacio; Vásquez-Velázquez, Ana Isabel; Aguayo-Orozco, Thania Alejandra; Delgadillo- Pérez, Saturnino & Domínguez, María Guadalupe
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.
Keywords
22q11.2 deletion; DiGeorge syndrome; velocardiofacial syndrome; congenital heart defects; tetralogy of Fallot; craniofacial abnormalities
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