Microarray analysis in pregnancies with isolated unilateral kidney agenesis.

Area of Science:

• Prenatal diagnostics
• Medical genetics
• Fetal medicine

Background:

• Isolated solitary kidney (unilateral renal agenesis) is a common fetal anomaly.
• The association between isolated solitary kidney and submicroscopic chromosomal aberrations is not well-established.
• Chromosomal microarray analysis (CMA) is a key tool for detecting submicroscopic chromosomal abnormalities.

Purpose of the Study:

• To investigate the risk of submicroscopic chromosomal aberrations in fetuses with apparently isolated solitary kidney.
• To compare the rate of clinically significant CMA findings in isolated solitary kidney pregnancies with control groups.

Main Methods:

• Retrospective data acquisition from the Israeli Ministry of Health database.
• Inclusion of 81 pregnancies with isolated unilateral kidney agenesis undergoing CMA (January 2013 - September 2016).
• Comparison of CMA findings with a systematic review of 9,792 cases and local data of 5,541 pregnancies undergoing CMA for maternal request.

Main Results:

• Two of 81 pregnancies (2.47%) with isolated solitary kidney showed copy number variants consistent with deletion syndromes (16p11.2-16p12.2 and 22q11.21 microdeletion).
• One variant of unknown significance was also identified.
• The relative risk for pathogenic CMA findings in isolated unilateral renal agenesis was not significantly different compared to control populations.

Conclusions:

• Isolated solitary kidney in fetuses is not associated with a significantly increased risk of submicroscopic chromosomal aberrations.
• Chromosomal microarray analysis (CMA) in pregnancies with unilateral renal agenesis is useful to a similar degree as in the general population.
• The diagnostic utility of CMA remains consistent across different indications, including isolated renal anomalies.