Clinical diagnostic exome evaluation for an infant with a lethal disorder: genetic diagnosis of TARP syndrome and expansion of the phenotype in a patient with a newly reported RBM10 alteration

Zöe Powis, Alexa Hart, Sara Cherny, Igor Petrik, Erika Palmaer, Sha Tang, Carolyn Jones

Diagnostic Exome Sequencing (DES) has been shown to be an effective tool for diagnosis individuals with suspected genetic conditions. We report a male infant born with multiple anomalies including bilateral dysplastic kidneys, cleft palate, bilateral talipes, and bilateral absence of thumbs and first toes. Prenatal testing including chromosome analysis and microarray did not identify a cause for the multiple congenital anomalies. Postnatal diagnostic exome studies (DES) were utilized to find a molecular diagnosis for the patient. Exome sequencing of the proband, mother, and father showed a previously unreported maternally inherited RNA binding motif protein 10 (RBM10) c.1352_1353delAG (p.E451Vfs*66) alteration. Mutations in RBM10 are associated with TARP syndrome, an X-linked recessive disorder originally described with cardinal features of talipes equinovarus, atrial septal defect, Robin sequence, and persistent left superior vena cava. DES established a molecular genetic diagnosis of TARP syndrome for a neonatal patient with a poor prognosis in whom traditional testing methods were uninformative and allowed for efficient diagnosis and future reproductive options for the parents. Other reported cases of TARP syndrome demonstrate significant variability in clinical phenotype. The reported features in this infant including multiple hemivertebrae, imperforate anus, aplasia of thumbs and first toes have not been reported in previous patients, thus expanding the clinical phenotype for this rare disorder.