Human earwax consists of wet and dry types. Dry earwax is frequent in East Asians, whereas wet earwax is common in other populations. Here we show that a SNP, 538G --> A (rs17822931), in the ABCC11 gene is responsible for determination of earwax type. The AA genotype corresponds to dry earwax, and GA and GG to wet type. A 27-bp deletion in ABCC11 exon 29 was also found in a few individuals of Asian ancestry. A functional assay demonstrated that cells with allele A show a lower excretory activity for cGMP than those with allele G. The allele A frequency shows a north-south and east-west downward geographical gradient; worldwide, it is highest in Chinese and Koreans, and a common dry-type haplotype is retained among various ethnic populations. These suggest that the allele A arose in northeast Asia and thereafter spread through the world. The 538G --> A SNP is the first example of DNA polymorphism determining a visible genetic trait.
We initially performed exome-sequencing 11 of the two UV S S-A patients, Kps3 and XP24KO (details described in Methods, Supplementary Note, Table 2c). The patients were homozygous for c.367A>T mutation in UVSSA, which led to a premature termination, p.Lys123* (Fig. 1a, b). We identified the same homozygous mutation in Kps2 (sib. of Kps3), and a homozygous c.87delG, causing a frameshift p.Ile31Phefs*9, in an Israeli patient UV S S24TA (Fig. 1b, c, Supplementary Note, Supplementary Fig. 1). The identified mutations are summarized in Fig. 1d. We did not detect the 80kDa UVSSA protein in any of the UV S S-A patients (Fig. 1e). We additionally examined several mild xeroderma pigmentosum (XP) cases; in one such case, XP70TO 12 (Supplementary Table 1), we identified a homozygous p.Cys32Arg, in the UVSSA (Fig. 1c, d), implying that XP70TO is also in the UV S S-A group. The mutant protein was stably expressed in XP70TO cells (Fig. 1f, Supplementary Fig. 2a-d). 4Allele frequencies of the identified mutations in a control population were examined (Supplementary Note, Supplementary Fig. 3a). Haploinsufficiency for UVSSA is negligible as the parents of Kps2/Kps3 showed no symptoms 4 . In parallel with exome-sequencing, we performed whole-genome SNP-genotyping to identify runs-of-homozygosity (ROH) shared among the patients. We identified three overlapping-ROHs (> 1Mbps) on autosomes, one of which encompasses the UVSSA locus (Fig. 1g, Supplementary Table 3a, b, Supplementary Fig. 3b, c). No chromosome copy number variation was detected (Supplementary Fig. 3d).The above findings strongly suggest that the mutations in UVSSA in the UV S S-A patients are causal for the disease; we therefore, next examined the NER-activities in the UV S S-A cells (Fig. 2). Unscheduled-DNA-synthesis (UDS 13 , defective in XP) was nearly normal; however, RNA-synthesis-recovery (RRS 14 , defective in UV S S and in CS) was reduced in all cell-strains mutated in UVSSA ( Fig. 2a, b; UDS and RRS were measured using a recently-developed rapid non-radioactive system 15,16 ). Similarly, siRNA-based depletion of the UVSSA gene (Fig. 2c) caused a drastic reduction of RRS (Fig. 2d, Supplementary Fig. 4), whereas UDS was unaffected (Fig. 2e). Ectopic-expression of the wild-type UVSSA cDNA in UV S S-A cells restored normal RRS ( Fig. 2f; V5-tagged-UVSSA immunofluorescent-staining shown in Fig. 2g), while it did not affect RRS-level in normal, CS-A, or CS-B cells; neither ERCC8 nor ERCC6 cDNA expression in UV S S-A cells restored the RRS-level.We conclude that KIAA1530/UVSSA is the causal gene for UV S S-A.ERCC8 and ERCC6 genes are responsible for both CS and UV S S 7,8 . To evaluate whether UVSSA mutations may also result in CS-phenotypes, we sequenced 5 the UVSSA gene of 61 CS-patients whose genetic defects had not yet been determined (Supplementary Table 4). We found no obvious mutations except for four novel heterozygous changes. These changes as well as the SNPs, also found in control and UV S S-A individuals, do not affect the RRS-activity (Suppleme...
Array using 2,173 BAC clones covering the whole human genome has been constructed. All clones spotted were confirmed to show a unique signal at the predicted chromosomal location by FISH analysis in our laboratory. A total of 30 individuals with idiopathic mental retardation (MR) were analyzed by comparative genomic hybridization using this array. Three deletions, one duplication, and one unbalanced translocation could be detected in five patients, which are likely to contribute to MR. The constructed array was shown to be an efficient tool for the detection of pathogenic genomic rearrangements in MR patients as well as copy number polymorphisms (CPNs).
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