Chromosome 22q11 copy number variants and single ventricle CHD

CHD is an important phenotypic feature of chromosome 22q11.2 copy number variants. Biventricular repair is usually possible, however there are rare reports of patients with chromosome 22q copy number variants and functional single ventricle cardiac disease.

This is a single centre retrospective review of patients with chromosome 22q copy number variants who underwent staged single ventricle reconstructive surgery between 1 July, 1984 and 31 December, 2020.

Seventeen patients met inclusion criteria. The most common diagnosis was hypoplastic left heart syndrome (n = 8) and vascular anomalies were present in 13 patients. A microdeletion of the chromosome 22 A-D low-copy repeat was present in 13 patients, and the remaining had a duplication. About half of the patients had documented craniofacial abnormalities and/or hypocalcaemia, and developmental delay was very common. Fifteen patients had a Norwood operation, 10 patients had a superior cavopulmonary anastomosis, and 7 patients had a Fontan. Two patients had cardiac transplantation after Fontan. Overall survival is 64% at 1 year, and 58% at 5 and 10 years. Most deaths occurred following Norwood operation (n = 5).

CHD necessitating single ventricle reconstruction associated with chromosome 22q copy number variants is not common, but typically occurs as a variant of hypoplastic left heart syndrome with the usual cytogenetic microdeletion. The most common neonatal surgical intervention performed is the Norwood, where most of the mortality burden occurs. Associated anomalies and medical issues may cause additional morbidity after cardiac surgery, but survival is similar to infants with other types of single ventricle disease.