High-level mosaic trisomy 9 at amniocentesis in a pregnancy associated with intrauterine growth restriction, a positive non-invasive prenatal testing for trisomy 9, cytogenetic discrepancy between cultured amniocytes and uncultured amniocytes, perinatal progressive decrease of the trisomy 9 cell line, a heterozygous missense mutation of the PIEZO2 gene and an adverse fetal outcome.