Compound heterozygous ROBO1 gene variants in a neonate with congenital hypopituitarism, dysmorphic features and midline abnormalities: a case report and review of the literature.

Objectives: The majority of congenital hypopituitarism (CH) cases remain genetically unexplained. The transmembrane receptor Roundabout-1 (ROBO1), activated through interaction with SLIT-family proteins, plays crucial role in axonal guidance, branching, targeting, and midline axonal crossing. ROBO1 variants have been associated with pituitary stalk interruption syndrome and highly variable pituitary-phenotypes, ranging from isolated growth hormone deficiency (IGHD) to combined pituitary hormone deficiency (CPHD). This study aimed to investigate the genetic basis of CH in a newborn and to review current evidence linking ROBO1 variants with CH.

Case presentation: We report the presence of two ROBO1 variants in compound heterozygosity, the NM_002941:c.2914G>A, p.(Ala972Thr) and the novel NM_002941:c.3757G>A, p.(Val1253Met), as well as the identification of the novel NOTCH3 variant NM_000435:c.1505C>T, p.(Ser502Phe) and the novel GPR161 variant NM_001375883.1:c.1117C>T, p.(His373Tyr), in a newborn with CPHD, dysmorphic features and midline abnormalities.

Conclusions: This case, together with accumulating evidence, supports ROBO1 as a potential causative gene for CH. ROBO1 should be considered during genetic evaluation of patients with CH and midline abnormalities. The co-occurrence of NOTCH3 and GPR161 variants raises the possibility of an oligogenic or multigenic etiology. The cross-talk between ROBO/SLIT and NOTCH signaling pathways may contribute to the complex phenotype observed and warrants further functional investigation.