Fetal Phenotype and Prenatal Diagnosis of Kabuki Syndrome

Kabuki syndrome (MIM 147920) is an autosomal dominant rare disease featured with multiple malformations and mental retardation. The main clinical manifestations of Kabuki syndrome are characteristic facial features, skeletal abnormalities, dermatoglyphic abnormalities, postpartum growth retardation, mild to moderate mental retardation, as well as other structural and functional abnormalities that may involve multiple systems. The establishment of diagnosis needs to be combined with clinical phenotype and the discovery of pathogenic mutation. Compared with the abundant descriptions and records of genotype-phenotype of postpartum patients, few prenatal diagnosis cases of Kabuki syndrome had been reported, which partially result from lacking the knowledge of its phenotype in fetuses that might suggest the diagnosis. This report performed comprehensive prenatal examinations to identify a fetus's etiology with multiple structural anomalies characterized by ascites, thickening of local skin, and cardiac abnormalities. We ruled out intrauterine infection, thalassemia, and chromosome abnormality by corresponding tests. Finally, trio whole-exome sequencing revealed a de novo heterozygous variation c.15641g > A (p.r5214h) in exon 48 of the KMT2D gene was the fetus's genetic pathogeny causing Kabuki syndrome. This result suggests that Kabuki syndrome should be in the suspected etiology list for prenatal hydrops/ascites. Our study confirmed that prenatal whole-exome sequencing is an efficient tool for diagnosing fetal abnormalities, and a multidisciplinary team is necessary for providing pregnancy guidance to patients.