It is possible in principle to diagnose cystinosis prenatally from measurement of intracellular cystine in chorionic villus of amniocyte cultures, but we have concerns about formal validation of the tests to assure compliance with clinical laboratory standards.  Also, molecular testing using DNA methods has become available and generally can provide the most definitive answer. Accordingly, we no longer offer prenatal testing. Molecular testing is available (refer to  GeneTests.org).