Typically in ARPKD, the kidneys appear to be larger than normal. In some babies, prenatal ultrasound can detect the enlarged kidneys as early as 18 weeks after conception. Some families may also hear their doctor say the kidneys look “echogenic” (more white) during an ultrasound, which can be an indicator of kidney problems such as ARPKD.
Prenatal genetic testing is possible using samples from either chorionic villus sampling or amniocentesis. These genetic tests can either involve a direct search of the gene for mutations or an indirect association using linkage analysis. For linkage analysis, DNA samples are required from the fetus, a previously affected child, and the parents.
Another option for pre-natal diagnosis in affected families is a recently developed procedure called pre-implantation genetic diagnosis, or PGD. This is an early form of genetic diagnosis that involves the detection of specific genetic abnormalities in single cells taken from fertilized human embryos. The PGD procedure involves in vitro fertilization whereby eggs harvested from a mother are fertilized in a laboratory with the father’s sperm. Then, the fertilized embryos are tested for ARPKD by removing one or two cells for genetic analysis. Embryos that are diagnosed as free of the disorder are then placed in the uterus with the intent to initiate a pregnancy.