Pathogenic Variants in TUBGCP6 of Familial Microcephaly and Chorioretinopathy

Microcephaly and chorioretinopathy type 1 (MCCRP1) is an autosomal recessive syndrome characterized by severe microcephaly, facial dysmorphisms, chorioretinopathy, and developmental delays. This rare condition is caused by homozygous or compound heterozygous pathogenic variants in the Tubulin Gamma Complex Component 6 (TUBGCP6) gene. We present 2 siblings from a non-consanguineous family in Indonesia diagnosed with MCCRP1. Both had a history of intrauterine growth retardation (IUGR) and were born with microcephaly and low birth weight. They exhibited developmental delays and hyperactive behavior. Facial dysmorphisms included upslanting palpebral fissures, strabismus, long philtrum, and a low anterior hairline. Ophthalmologic examination revealed chorioretinopathy in both siblings, while cardiac and hearing evaluations were normal. Microarray analysis revealed no likely pathogenic copy number variants (CNVs). Whole exome sequencing (WES) was performed on DNA from the siblings and their parents. The variant analysis identified a paternal pathogenic splice variant c.2066-6A>G and a maternal pathogenic nonsense variant c.3393G>A in the TUBGCP6 gene (NM_020461.4) in both siblings, indicating a compound heterozygous variant. This is the first case report of familial MCCRP1 in Indonesia, presenting both clinical features and genetic analysis of the TUBGCP6 gene.