[Meckel Gruber syndrome: about a rare case]

Identification of a novel RPGRIP1 mutation in an Iranian family with leber congenital amaurosis by exome sequencing

Leber congenital amaurosis (LCA) is a heterogeneous, early-onset inherited retinal dystrophy, which is associated with severe visual impairment. We aimed to determine the disease-causing variants in Iranian LCA and evaluate the clinical implications. Clinically, a possible LCA disease was found through diagnostic imaging, such as fundus photography, autofluorescence and optical coherence tomography. All affected patients showed typical eye symptoms associated with LCA including narrow arterioles, blindness, pigmentary changes and nystagmus. Target exome sequencing was performed to analyse the proband DNA. A homozygous novel c. 2889delT  (p.P963 fs) mutation in the RPGRIP1 gene was identified, which was likely the deleterious and pathogenic mutation in the proband. Structurally, this mutation lost a retinitis pigmentosa GTPase regulator (RPGR)-interacting domain at the C-terminus which most likely impaired stability in the RPGRIP1 with the distribution of polarised proteins in the cilium connecting process. Sanger sequencing showed complete co-segregation  in this pedigree. This study provides compelling evidence that the c. 2889delT  (p.P963 fs) mutation in the RPGRIP1 gene works as a pathogenic mutation that contributes to the progression of LCA.

Meckel Gruber syndrome associated with anencephaly-an unusual reported case

Meckel–Gruber syndrome (MGS) is a rare and lethal ciliopathic disorder, with the incidence ranging between 1 in 13 000–400 000 live births. MGS is characterized by multisystem developmental malformations with the classical features of renal cystic dysplasia, occipital encephalocele and post-axial polydactyly. Except for occipital encephalocele, the CNS abnormalities associated with MGS that are less frequently reported include hydrocephaly, anencephaly or malformation of cerebellum. Our presented case of MGS is associated with anencephaly and other facial abnormalities. This kind of ailment is infrequently reported in literature.