Presentation: Child with an ectopic kidney

A 6-year-old boy was found to have an ectopic right kidney located in the pelvis on an ultrasound scan for unexplained abdominal pain. The left kidney was normal in size and location. His renal function was normal. His 36-year-old mother had been referred to the renal clinic last year after being identified with chronic kidney disease in pregnancy. Her renal ultrasound showed unilateral renal agenesis.

Consider genomic testing for:

• Clinically significant non-syndromic congenital anomalies of the kidney and urinary tract (CAKUT), if the patient also has a first-degree relative with CAKUT or unexplained end-stage renal disease.
  • Note: In some cases, additional family history information may suggest that testing would be beneficial. You can check criteria with your local testing laboratory.
• Families in which there are only minor forms of CAKUT are unlikely to benefit from genomic testing (for example, isolated vesico-ureteric reflux, duplex kidney, posterior urethral valves).
• When CAKUT occurs with additional syndromic features. This is because in these instances, it is likely to have a monogenic cause.
• CAKUT with a personal or family history of diabetes or renal cysts.

• Consult the National Genomic Test Directory. Here you can access the rare and inherited disease eligibility criteria document for information about individual tests and their associated eligibility criteria. You can also access a spreadsheet of all available tests.
  • For information about how to arrange testing in Wales, Scotland or Northern Ireland, see our Knowledge Hub resource ‘Genomic testing in the devolved nations’.
  • To find out which genes are included on different gene panels, see the NHS Genomic Medicine Service (GMS) Signed-Off Panels Resource.
•  Decide which of the panels best suits the needs of your patient/family:
  • R199 CAKUT-familial: This indication uses genome-wide microarray to identify any copy number variants that might be associated with CAKUT.
  • R27 Paediatric disorders and R89 Ultra-rare and atypical monogenic disorders: These tests may be considered for individuals with complex or syndromic presentations. R27 includes microarray and a whole genome sequencing (WGS) ‘super-panel’. R89 includes microarray and WGS panels selected by the requesting clinician. These tests require authorisation from clinical genetics.
  • R141 Monogenic diabetes: This test should be used when there is a personal or family history of diabetes or renal cysts. It includes whole exome sequencing or a medium-sized panel and multiplex ligation-dependent probe amplification (MLPA).
  • R240 Diagnostic testing for known mutation(s): This indication can be used if a patient who is clinically affected with CAKUT has a family member with a known pathogenic or likely pathogenic variant. (Note that variable penetrance is common.) In this situation, the laboratory will only test for the known familial variant.
  • R242 Predictive testing for known familial mutation(s): This indication is for a predictive (also known as presymptomatic) test and should be used for unaffected individuals who have a family member with a known pathogenic or likely pathogenic variant. This test can only be requested by clinical genetics.
• For tests that do not include WGS, including R199, R141, R240 and R242:
  • Use your local Genomic Laboratory Hub (GLH) test order and consent (record of discussion) forms.
  • When testing in children, parental samples may be needed for interpretation of the proband’s result, for example to determine whether a variant is de novo or inherited. These samples may be requested by the testing laboratory or you may wish to contact clinical genetics.
• For WGS-based tests, such as R27 and R89 you will need to:
  • Complete an NHS GMS test order form with details of the affected child (proband) and their parents. Include details of the phenotype (using human phenotype ontology (HPO) terms) and the appropriate panel name(s) with associated R number (see how to complete a test order form for WGS for support).
  • Complete an NHS GMS record of discussion form for each person being tested. If you are undertaking trio testing of an affected individual and their parents, you will need to complete three forms. See how to complete a record of discussion form for support.
  • Submit parental samples alongside the child’s sample where possible to aid interpretation, especially for the larger WGS panels. Where this is not possible, for example if the child is in care and there is no access to parents, or if one parent is unavailable for testing, the child’s sample may still be submitted.
• These tests are DNA-based, so an EDTA sample (purple-topped tube) is required.

For clinicians

• Genomics England: NHS Genomic Medicine Service (GMS) signed off panels resource
• MedlinePlus: Congenital anomalies of kidney and urinary tract
• NHS England: National Genomic Test Directory
• UK Kidney Association: Congenital Anomalies of the Kidneys and Urinary Tracts, Rare Disease Group

For patients

• infoKID (information for parents and carers of children with kidney conditions)
• UK Kidney Association: Congenital Anomalies of the Kidneys and Urinary Tracts