Significant association between IRF6 820G→A and non-syndromic cleft lip with or without cleft palate in the Thai population

Background: Previous data have shown an association between DNA sequence variants in the IRF6 gene and an increased risk of non-syndromic cleft lip with or without cleft palate (CL/P) in some populations. Objective: To investigate Thai CL/P patients and relative for a 820G→A polymorphism. Subjects: 192 CL/P Thai patients, 177 of their mothers, 73 of their fathers, and 278 controls. Results: There were significant differences in the frequency distributions of both genotypes (p = 0.02) and alleles (p = 0.04) among probands as compared with the control group. The odds ratio calculated for the patients having the GG genotype compared with the other two genotypes (GA and AA) was 1.67 (95% confidence interval, 1.13 to 2.47). This pattern is consistent with a recessive effect of the G allele. No association between any of the parents' genotypes and CL/P was found. The IRF6 820G→A was responsible for 16.7% of the genetic contribution to CL/P. Conclusions: The findings confirm that IRF6 820G→A is associated with CL/P

Mutational and phenotypic expansion of ATP1A3-related disorders: Report of nine cases.

Background: Mutations in the ATP1A3 gene are known to be the cause of three distinct neurological syndromes including alternating hemiplegia of childhood (AHC), rapid-onset dystonia parkinsonism (RDP) and cerebellar ataxia, arefexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS). Recent studies have suggested the broader diversity of ATP1A3-related disorders. This study aimed to investigate the clinical spectrum in patients carrying causative mutations within the ATP1A3 gene.Method: The medical histories of nine unrelated patients with diverse phenotypes harboring variants in ATP1A3 were retrospectively analyzed after they were referred to a tertiary epilepsy center in one of the two different health care systems (Germany or Thailand). Clinical features, neurophysiological data, imaging results, genetic characteristics and treatments were reviewed.Results: Three patients harbor novel mutations in the ATP1A3 gene. Atypical clinical features and imaging findings were observed in two cases, one with hemiplegia-hemiconvulsion-epilepsy syndrome, and the other with neurodegeneration with brain iron accumulation. All nine patients presented with intellectual impairment. Alternating hemiplegia of childhood (AHC) was the most common phenotype (67%). Flunarizine and topiramate led to symptom reduction in 83% and 25% of AHC cases administered, respectively.Conclusion: The present case series expands the clinical and genetic spectrum of ATPIA3-related disorders

MBTPS2 mutations cause defective regulated intramembrane proteolysis in X-linked osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia. We identified an X-linked recessive form of OI caused by defects in MBTPS2, which encodes site-2 metalloprotease (S2P). MBTPS2 missense mutations in two independent kindreds with moderate/severe OI cause substitutions at highly conserved S2P residues. Mutant S2P has normal stability, but impaired functioning in regulated intramembrane proteolysis (RIP) of OASIS, ATF6 and SREBP transcription factors, consistent with decreased proband secretion of type I collagen. Further, hydroxylation of the collagen lysine residue (K87) critical for crosslinking is reduced in proband bone tissue, consistent with decreased lysyl hydroxylase 1 in proband osteoblasts. Reduced collagen crosslinks presumptively undermine bone strength. Also, proband osteoblasts have broadly defective differentiation. These mutations provide evidence that RIP plays a fundamental role in normal bone development