An exploratory study of predisposing genetic factors for DiGeorge/velocardiofacial syndrome
نویسندگان
چکیده
DiGeorge/velocardiofacial syndrome (DGS/VCFS) is a disorder caused by a 22q11.2 deletion mediated by non-allelic homologous recombination (NAHR) between low-copy repeats (LCRs). We have evaluated the role of LCR22 genomic architecture and PRDM9 variants as DGS/VCFS predisposing factors. We applied FISH using fosmid probes on chromatin fibers to analyze the number of tandem repeat blocks in LCR22 in two DGS/VCFS fathers-of-origin with proven 22q11.2 NAHR susceptibility. Results revealed copy number variations (CNVs) of L9 and K3 fosmids in these individuals compared to controls. The total number of L9 and K3 copies was also characterized using droplet digital PCR (ddPCR). Although we were unable to confirm variations, we detected an additional L9 amplicon corresponding to a pseudogene. Moreover, none of the eight DGS/VCFS parents-of-origin was heterozygote for the inv(22)(q11.2) haplotype. PRDM9 sequencing showed equivalent allelic distributions between DGS/VCFS parents-of-origin and controls, although a new PRDM9 allele (L50) was identified in one case. Our results support the hypothesis that LCR22s variations influences 22q11.2 NAHR events, however further studies are needed to confirm this association and clarify the contribution of pseudogenes and rare PDRM9 alleles to NAHR susceptibility.
منابع مشابه
Prevalence of 22q11 microdeletions in DiGeorge and velocardiofacial syndromes: implications for genetic counselling and prenatal diagnosis.
Deletions of chromosome 22q11 have been seen in association with DiGeorge syndrome (DGS) and velocardiofacial syndrome (VCFS). In the present study, we analysed samples from 76 patients referred with a diagnosis of either DGS or VCFS to determine the prevalence of 22q11 deletions in these disorders. Using probes and cosmids from the DiGeorge critical region (DGCR), deletions of 22q11 were detec...
متن کاملVelocardiofacial syndrome.
Velocardiofacial syndrome is one of the most common multiple-anomaly syndromes in humans. With its many otolaryngologic manifestations and its almost ubiquitous effects on speech, language, hearing, immune dysfunction, and airway problems, velocardiofacial syndrome may be the most common genetic disorder seen by pediatric otolaryngologists. Individuals affected with velocardiofacial syndrome lo...
متن کامل22q11.2 deletion syndrome
DiGeorge and velocardiofacial syndrome (22q11.2 deletion syndrome) is the most common microdeletion disorder in humans and, hence, one of the most common multiple malformation syndromes, with an estimated prevalence of 1 in 2000 to 1 in 4000. It is characterized by craniofacial anomalies, conotruncal heart disease, thymic aplasia and hypoplasia, hypocalcemia, and psychiatric illness. In this ar...
متن کاملNormal cardiovascular development in mice deficient for 16 genes in 550 kb of the velocardiofacial/DiGeorge syndrome region.
Hemizygous interstitial deletions in human chromosome 22q11 are associated with velocardiofacial syndrome and DiGeorge syndrome and lead to multiple congenital abnormalities, including cardiovascular defects. The gene(s) responsible for these disorders is thought to reside in a 1.5-Mb region of 22q11 in which 27 genes have been identified. We have used Cre-mediated recombination of LoxP sites i...
متن کاملChildren and adolescents with velocardiofacial syndrome: a volumetric MRI study.
OBJECTIVE Velocardiofacial syndrome is a common genetic condition often accompanied by mild cognitive impairment. Children and adolescents with velocardiofacial syndrome also are at greater risk for developing serious neuropsychiatric disorders in adulthood, particularly schizophrenia-like disorders. The purpose of this preliminary study was to 1) elucidate through brain imaging the neurobiolog...
متن کامل