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Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the glucocerebrosidase (GBA) gene, leading to a deficiency of lysosomal β-glucosidase and accumulation of glycosphingolipids in macrophages. We studied five Thai families with GD (four with GD type 1 and one with GD type 2). Using long-template PCR, PCR using specific primers for the functional gene, direct sequencing of all coding regions of GBA and restriction enzyme digestions, all 10 mutant alleles were successfully identified. The common c.1448T>C (p.L483P or L444P) mutation was identified in 60% of mutant alleles. Of the two patients homozygous for the p.L483P (L444P) mutation, one died from hepatic failure at age 16 years and the other died from sepsis at age 12 years. This p.L483P (L444P) mutation was found in four different haplotypes, suggesting that it was a recurrent mutation, not caused by a founder effect. Two novel mutations, a missense (c.1204T>C, p.Y402H), and a termination codon mutation (c.1609T>C, p.X537A) were found. Studies to determine the molecular pathomechanism of the p.X537A mutation, the first of its kind in this gene, showed that it decreased the amount of protein being expressed and the enzymatic activity, while it was still correctly localized. [ABSTRACT FROM AUTHOR]

Isolated cleft palate (CP) is common in humans and has complex genetic etiologies. Many genes have been found to contribute to CP, but the full spectrum of genes remains unknown. PCR-sequencing of the entire coding regions and the 3′ untranslated region (UTR) of the platelet-derived growth factor receptor alpha (PDGFRa) and the microRNA (miR), miR-140 identified seven novel single base-pair substitutions in the PDGFRa in 9/102 patients with CP (8.8%), compared with 5/500 ethnic-matched unaffected controls (1%) (the two-tailed P-value<0.0001). Of these seven, four were missense mutations in the coding regions and three in the 3′UTR. Frequencies of four changes (three in coding, one in 3′UTR) were statistically different from those of controls (P-value<0.05). The c.*34G>A was identified in 1/102 cases and 0/500 controls. This position is conserved in primates and located 10 bp away from a predicted binding site for the miR-140. Luciferase assay revealed that, in the presence of miR-140, the c.*34G>A significantly repressed luciferase activity compared with that of the wild type, suggesting functional significance of this variant. This is the first study providing evidence supporting a role of PDGFRa in human CP. [ABSTRACT FROM AUTHOR]

• The mutations in two different genes should be sought in the patients with complex phenotypes. • The c.1531G>T in COL1A2 leading to OI and c.364C>T (p.R122W) in LHX4 to CPHD were found in a Thai boy. • The incomplete penetrance and loss-of-function are the features of p.R122W mutation in LHX4. • The mutation spectra of COL1A2 and LHX4 and pathomechanism of LHX4 are expanded. Genetic disorders have been shown to co-occur in individual patient. A Thai boy with features of osteogenesis imperfecta (OI) and combined pituitary hormone deficiency (CPHD) was identified. The causative mutations were investigated by whole exome and Sanger sequencing. Pathogenicity and pathomechanism of the variants were studied by luciferase assay. The proband was found to harbor a novel de novo heterozygous missense mutation, c.1531G > T (p.G511C), in COL1A2 leading to OI and a heterozygous missense variant, c.364C > T (p.R122W), in LHX4. The LHX4 p.R122W has never been reported to cause CPHD. The variant was predicted to be deleterious and found in the highly conserved LIM2 domain of LHX4. The luciferase assays revealed that the p.R122W was unable to activate POU1F1 , GH1 , and TSHB promoters, validating its pathogenic effect in CPHD. Moreover, the variant did not alter the function of wild-type LHX4 , indicating its hypomorphic pathomechanism. In conclusion, the novel de novo heterozygous p.G511C mutation in COL1A2 and the heterozygous pathogenic p.R122W mutation in LHX4 were demonstrated in a patient with OI and CPHD. This study proposes that the mutations in two different genes should be sought in the patients with clinical features unable to be explained by a mutation in one gene. [ABSTRACT FROM AUTHOR]

Objective: Mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome), a rare autosomal recessive lysosomal storage disease, is caused by mutations in the N-acetylgalactosamine-4-sulfatase ( arylsulfatase B, or ARSB) gene, resulting in a deficiency of ARSB activity. This study aimed to characterize the clinical and molecular features of four unrelated Thai patients with MPS VI. Two were products of consanguineous marriages. Materials and Methods: The diagnosis was confirmed by biochemical and genetic tests. We performed mutation analysis by polymerase chain reaction-sequencing on the entire coding region of the ARSB gene. Array-based comparative genomic hybridization (aCGH) analysis combined with direct sequencing was also used to search for a deletion boundary. Results: The causative mutations were detected in all cases. Of four different mutations identified, three have never been previously described, which included two missense mutations (p.C155Y and p.R388T) and a deletion encompassing exons 2 and 3. Both missense mutations were absent in 110 unaffected ethnic-matched control chromosomes and an in-house database of 180 Thai exomes. The p.C155Y and p.R388T mutations were located in highly conserved residues. A CGH analysis combined with direct sequencing identified the breakpoints of a large 13,788 base pair deletion. It is the largest deletion of ARSB described to date in patients with MPS VI. Conclusion: This study expanded the known mutational spectrum of ARSB; we identified three novel mutations; two of which are missense mutations and one that represents the largest deletion mutation identified to date in this gene. [ABSTRACT FROM AUTHOR]