[Prenatal diagnosis of Rasopathies in Ras/MAPK signaling pathway]

RASopathies are a group of disorders caused by germline variants of genes involved in RAS/MAPK pathway with overlapping features which may complicate their diagnosis. Since almost all RASopathies are autosomal dominant inherited disorders, the affected families may give birth to multiple children with the disease. Owning to the advance in sequencing technology, the genotype-phenotype correlation of RASopathies has become clearer in recent years, and genetic testing is now available in many places, which make prenatal diagnosis for couples with increased risk possible. For de novo variants of RASopathies, prenatal diagnosis is still difficult as the findings in routine ultrasonography are not specific enough. Nevertheless, certain findings may still be used as clues for prenatal diagnosis. This article overviews the common disorders of RASopathies, with an emphasis on the features that can be used as clues for the prenatal diagnosis of RASopathies.