Long-Term Follow Up of Two Patients With Variants in the Cluster 1031-1159 of TRRAP Gene: Expanding the Phenotype of Developmental Delay With or Without Dysmorphic Facies and Autism

The transformation/transcription domain-associated protein (TRRAP) gene encodes a large multidomain protein, a member of the phosphatidylinositol 3-kinase-related kinase (PIKK) family. TRRAP is a component of the histone acetyltransferase (HAT) complex, and it plays an important role in gene transcription, DNA repair, and cell-cycle regulation. Heterozygous missense variants in the TRRAP gene have been associated with a multiple system condition known as developmental delay with or without dysmorphic facies and autism (DEDDFA; OMIM #618454), hearing loss, and different types of cancer. Strong genotype–phenotype correlation has been observed in DEDDFA, where missense variants located in the clustering between residues 1031–1159 result in more pronounced facial anomalies associated with a variable degree of intellectual disability. Here, we report two Brazilian females with syndromic orofacial cleft, presenting very similar atypical facial phenotypes and multisystem anomalies. Both had a severe phenotype with global developmental delay, ranging from moderate to severe, and one of them had a severe behavior disorder associated with non-verbal autism while the other had inguinal cancer. Next-generation sequencing showed that both displayed heterozygous missense variants in the TRRAP gene, clustering at the 1031-1159 amino acid residues. These cases reinforce the genotype–phenotype correlation of variants in the TRRAP gene with a possible new domain in the cluster 1031-1159.