Vertebral, Cardiac, Renal and Limb Defects Syndrome 2
Autosomal recessive
Caused by changes in both copies of KYNU, an enzyme in the pathway that makes NAD from the amino acid tryptophan. Low NAD during embryonic development disrupts formation of several organs.
Signs and symptoms
Vertebral segmentation defects, heart defects, kidney anomalies and limb differences are typical, sometimes with short stature. Some children have developmental delay. Raised levels of xanthurenic acid, a tryptophan breakdown product, can be found in urine.
What a diagnosis changes
Care addresses each birth defect, with cardiac, renal and orthopaedic follow-up. In animal studies niacin supplementation in pregnancy prevented similar defects, but this has not been established in people. Carrier testing of relatives and genetic counselling are available.
Genes analysed
Also known as
VCRL2
