G MOONSAMY 1, H TANUDISASTRO 2, D HAHN 1,2, L ST HEAPS 1, S ALEXANDER 1,2, H MCCARTHY 1,2
1Children’s Hospital Westmead, Westmead, Australia, 2University of Sydney, Sydney, Australia
Background: Cat Eye Syndrome is a rare chromosomal disorder in which the short arm and a small region of the long arm of chromosome 22 (22pter-22q11) is present three (partial trisomy) to four times (partial tetrasomy). The distinctive eye abnormality is an iris coloboma that gave rise to the original description. The syndrome has multisystem involvement and although the association with kidney abnormalities are known they are little described in the literature. We present four cytogenetically confirmed patients with malformation of the kidney(s).
Case Series: Patient 1, male, presented at birth with high grade bilateral vesico-ureteric reflux, micrognathia, severe global developmental delay, and bilateral vestibular dysplasia. Patient 2, male, also presented at birth with a unilateral left multicystic dysplastic kidney, typical colobomas, total anomalous pulmonary venous return (TAPVR), imperforate anus and micrognathia. Patient 3, female, had a family history of unilateral renal agenesis and TAPVR. She presented antenatally with the same abnormalities. Patient 4 had a history of previous partial nephrectomy overseas for presumed non-functioning lower pole of left duplex system. He also had the typical colobomas and ear pits. Patients 1 and 2 have 22q11 duplication, Patient 3 (and mother) have triplication of the copy number variant (CNV) whereas patient 4 is mosaic for an additional ring chromosome 22.
Conclusion: The combination of renal anomalies with coloboma is highly suggestive of a genetic aetiology. While PAX2 associated renal coloboma syndrome is more common, this CNV is associated with a more complex phenotype requiring multi-disciplinary input and is easily diagnosed on a rapid and medicare rebatable microarray. The phenotype presented here, suggest an effect of this disorder on early ureteric bud formation.
Dr Glenda Moonsamy is an overseas trained graduate that is currently a paediatric renal fellow in the Sydney Children’s Hospital Network