Revealing the functions of novel mutations in RAB3GAP1 in Martsolf and Warburg micro syndromes

Purpose: Martsolf (MS) and Warburg micro syndromes (WARBM) are rare autosomal recessive inherited allelic disorders, which share similar clinical features including microcephaly, intellectual disability, brain malformations, ocular abnormalities, and spasticity. Here, we revealed the functions of novel mutations in RAB3GAP1 in a Turkish female patient with MS and two siblings with WARBM. We also present a review of MS patients as well as all reported RAB3GAP1 pathogenic mutations in the literature. Methods: We present a female with MS phenotype and two siblings with WARBM having more severe phenotypes. We utilized whole-exome sequencing to identify the molecular basis of these syndromes and confirmed suspected variants by Sanger sequencing. Quantitative (q) RT-PCR analysis was carried out to reveal the functions of novel splice site mutation detected in MS patient. Results: We found a novel homozygous c.2607-1G>C splice site mutation in intron 22 of RAB3GAP1 in MS patient and a novel homozygous c.2187_2188delinsCT, p.(Met729_Lys730delinsIleTer) mutation in exon 19 of RAB3GAP1 in the WARBM patients. We showed exon skipping in MS patient by Sanger sequencing and gel electrophoresis. qRT-PCR analysis demonstrated the reduced expression of RAB3GAP1 in the patient with the c.2607-1G>C splice site mutation compared to a healthy control individual. Conclusion: Here, we have studied two novel RAB3GAP1 mutations in two different phenotypes; a MS associated novel splice site mutation, and a WARBM1 associated novel deletion-insertion mutation. Our findings suggest that this splice site mutation is responsible for milder phenotype and the deletion-insertion mutation presented here is associated with severe phenotype

Anti-erosive effects of fluoride and phytosphingosine: an in vitro study

A selection of commercially available products containing stannous fluoride (SnF2)/sodium fluoride (NaF), SnF2/amorphous calcium phosphate (ACP), SnF2/NaF/ACP, tin (Sn)/fluorine (F)/chitosan were compared with phytosphingosine (PHS) with respect to their anti-erosive properties in vitro. One-hundred and twenty bovine enamel specimens were immersed in the respective product slurries for 2 min, twice daily. The formulations were diluted with either remineralization solution or artificial saliva. After each treatment, an erosive challenge was performed for 10 min, twice daily, using citric acid, pH 3.4. The specimens were stored in remineralization solution or artificial saliva until the next treatment-erosion challenge. After 10 d, tissue loss was determined using profilometry. Enamel softening was determined through surface microhardness measurements. Tissue-loss values (measured in μm and expressed as mean ± SD) for PHS, SnF2/NaF, SnF2/ACP, SnF2/ACP/NaF, and Sn/F/chitosan treatment groups and for the negative-control group, were, respectively, 35.6 ± 2.8, 15.8 ± 1.8, 22.1 ± 2.0, 22.9 ± 1.8, 16.2 ± 1.2, and 51.2 ± 4.4 in the presence of remineralization solution and 31.7 ± 3.3, 15.6 ± 2.9, 16.5 ± 2.7, 16.8 ± 2.1, 13.1 ± 3.0, and 50.7 ± 2.8 in the presence of artificial saliva. There were no significant differences in surface microhardness measurements between the treatment groups. In conclusion, PHS resulted in a significant reduction of tissue loss compared with the negative control, but in comparison, the toothpastes containing Sn2+ and F− ions were significantly more effective compared with PHS