[Improvement of genetic diagnostic strategy in velo-cardio-facial syndrome]

Velo-Cardio-Facial Syndrome (VCFS) is characterized by congenital heart defects (CHD), palatal abnormalities, facial dysmorphism, neonatal hypocalcemia, immune deficit, speech and learning disabilities. SVCF is caused by microdeletion 22q11.2. Microdeletion is detected by fluorescence in situ hybridization (FISH). The highly variable phenotype makes diagnosis and selection for FISH more difficult.

To retrospectively analyze and compare the phenotype of children with a clinical diagnosis of VCFS with/without 22q11 deletion; to verify the validity of literature guidelines and to describe combinations of clinical features that should lead to molecular analysis.

The present study was performed in 21 patients with a clinical diagnosis of VCFS. Methaphase chromosome spreads were prepared from phytohaemagglutinin stimulated lymphocyte culture by standard methods before FISH. The patients were divided into two groups according to FISH test: positive and negative.

The features commonly noticed in FISH positive patients were: palatal abnormalities/hypernasal speech, learning disabilities, facial dysmorphism, tapered fingers (6/6), CHD (5/6) and recurrent infections (2/6). In FISH negative patients the following were found: learning disabilities, CHD (12/15); facial dysmorphism (10/15), family history of CHD (7/15), short stature (6/15), hypocalcemia, tapered fingers (5/15), recurrent infections (3/15) and palatal cleft (2/15). In both groups, Tobias and McDonald-McGinn guidelines were positive.

VCFS has a highly variable phenotype. Our study suggests that 22q11.2 deletion analysis by FISH should be performed in patients who have at least 2 (newborn)/3 (child, adult) specific criteria: CHD, hypocalcemia, palatal abnormalities, facial dysmorphism, learning disabilities, digital anomalies, and immune deficit.