Case report of four siblings in southeast Turkey with a novel RAB3GAP2 splice site mutation: Warburg micro syndrome or Martsolf syndrome?

BACKGROUND: Warburg micro syndrome is a very rare autosomal recessive disorder characterized by a mutation in the RAB3GAP1, RAB3GAP2, RAB18, and TBC1D20 genes. Warburg Micro syndrome 2 and Martsolf syndrome are clinically overlapping conditions characterized by variable clinical signs counting postnatal growth retardation, cataract, intellectual deficiency, contractures, and central nervous system abnormalities due to RAB3GAP2 gene mutations. The RAB3GAP2 gene encodes a member of the Rab3 protein family, which is involved in regulated exocytosis of neurotransmitters and hormones.

CASE PRESENTATION: We describe four siblings from healthy consanguineous Turkish parents with developmental delay, congenital cataract, and speech delay. In this study, we performed whole exom sequencing (WES) in a index patient. WES analyses in proposita showed a homozygous c.1998 + 1 G > A mutation in RAB3GAP2 gene. After the Sanger confirmation, the same mutation was detected in the other three siblings.

CONCLUSION: The four siblings had a novel splice site mutation in RAB3GAP2. This report compares the symptoms and features of the our patients with clinical summary of Warburg Micro syndrome 2 and Martsolf syndrome. Further reports will make possible knowing of the genetic and clinical backgrounds of this orphan diseases. Abbreviation: MRI: Magnetic resonance imaging.