Monozygotic twins concordant for Cayler syndrome

Abstract

Deletions within chromosome band 22q11.2 are associated with a variety of conditions, although a simple genotype-phenotype correlation has not been established so far. Environmental factors, chance events, or a second hit theory were supported by two observations of monozygotic twins with 22q11.2 deletions and discordant phenotypes [Goodship et al., J Med Genet 1995;32:746-748; Fryer, J Med Genet 1996;33:173]. We present monozygotic twins concordant for 22q11.2 deletion and Cayler syndrome, favoring the view that there exists a predominant genetic determination of the del 22q11.2 phenotype. As these twins are diamniotic and dichorionic, they may offer a more reliable insight in genetic phenotype determination than the other published, probably monochorionic, twins who may have a discordant malformation by twinning itself.

Monozygotic twins with chromosome 22q11 deletion and discordant phenotypes: updates with an epigenetic hypothesis

“…In fact, most reports on monozygotic twin pairs with 22q11 deletions are reported to be phenotypically discordant. The exception to this pattern may be Rauch et al, 16 who reported on a pair of diamniotic and dichorionic monozygotic twins with 22q11.2 deletions who were concordant for Cayler syndrome. Even this pair had differences in the severity of the cardiac abnormality; twin 1 had a ventricular septal defect while twin 2 had tetralogy of Fallot.…”

Cardiac Registry Screening for DiGeorge Critical Region Deletion Using Loss of Heterozygosity Analysis

“…Anomalous embryonic neural crest cell migration within the 3rd and 4th branchial arches is postulated to account for developmental field defects in patients with these syndromes [5,6]. The variation in neural crest developmental abnormalities is reflected in that other phenotypes, such as CHARGE association, Opitz G/BBB syndrome, and Cayler syndrome, can also have congenital heart disease and microdeletions of 22q11.2 [7][8][9][10]. Although a majority of patients have sporadic deletions, case reports exist of familial transmission [11][12][13].…”

Clinical relevance of monosomy 22q11.2 in children with pulmonary atresia and ventricular septal defect

“…1). In addition one patient had sensoneuronal hearing loss, one patient had hexadactyly and one patient had hypoplasia of the depressor anguli oris muscle (Cayler syndrome) [24]. Hypoparathyroidism with symptomatic hypocalcaemia was present in one further patient.…”