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Background: Punctate palmoplantar keratoderma type 1 (PPPK1) presents in late childhood to adulthood with multiple small discrete hyperkeratotic papules on palms and soles. PPPK1 is an autosomal dominant skin disease caused by AAGAB mutations. It has been suggested that PPPK1 may be associated with an increased predisposition to systemic malignancies. Objectives: To evaluate the presence of AAGAB mutations in Canadian families with PPPK1 and the possible increased predisposition to systemic malignancies. Methods: Eighteen unrelated Canadian families with PPPK1 were recruited for this study. Genomic DNA was extracted from saliva and PCR amplification was performed for all AAGAB exons and exon/intron junctions. PCR products were sequenced and analyzed for mutations. A family history of malignancy was obtained from the index case and, when possible, from other family members. Results: We have identified 5 heterozygous AAGAB loss of function mutations in 11 families. The mutation c.370 C>T, p.Arg124* was the most prevalent and was identified in 6 families. A splice site mutation, c.451+3delAAGT, was identified in 2 families. The other mutations c.473delG, p.Gly158Glufs*0; c.550-551insAAT, p.Gly183*; and c.505-506 dupAA, p.Asn169Lysfs*6 were each identified in 1 family. Different cancers were reported in 11 families (Table 1 and Supplemental Figure S1). Conclusions: AAGAB mutations were found in 11 of 18 families with PPPK1. In some families there appears to be an association with cancer.

Basan syndrome is an autosomal dominant genodermatosis characterized by congenital adermatoglyphia, transient congenital facial milia, neonatal acral bullae, and absent or reduced sweating. Basan syndrome is rare and has been reported in only 10 kindreds worldwide. It is caused by variants in the skin-specific isoform of SMARCAD1, which starts with an alternative exon 1. All reported variants, except for one large deletion, are point mutations within the donor splice site of the alternative exon 1. In this paper, we report two families with Basan syndrome and describe two SMARCAD1 variants. In one family, we have identified a complex structural variant (a deletion and a nontandem inverted duplication) using whole-genome optical mapping and whole-genome sequencing. Although this variant results in the removal of the first nine exons of SMARCAD1 and exon 1 of the skin-specific isoform, it manifested in the typical Basan phenotype. This suggests that unlike the skin-specific isoform, a single copy of full-length SMARCAD1 is sufficient for its respective function. In the second family, whole-exome sequencing revealed a deletion of 12 base pairs spanning the exon‒intron junction of the alternative exon 1 of the skin-specific SMARCAD1 isoform. In conclusion, we report two additional families with Basan syndrome and describe two SMARCAD1 pathogenic variants.

Basan syndrome is an autosomal dominant genodermatosis characterized by congenital adermatoglyphia, transient congenital facial milia, neonatal acral bullae, and absent or reduced sweating. Basan syndrome is rare and has been reported in only 10 kindreds worldwide. It is caused by variants in the skin-specific isoform of SMARCAD1, which starts with an alternative exon 1. All reported variants, except for one large deletion, are point mutations within the donor splice site of the alternative exon 1. In this paper, we report two families with Basan syndrome and describe two SMARCAD1 variants. In one family, we have identified a complex structural variant (a deletion and a nontandem inverted duplication) using whole-genome optical mapping and whole-genome sequencing. Although this variant results in the removal of the first nine exons of SMARCAD1 and exon 1 of the skin-specific isoform, it manifested in the typical Basan phenotype. This suggests that unlike the skin-specific isoform, a single copy of full-length SMARCAD1 is sufficient for its respective function. In the second family, whole-exome sequencing revealed a deletion of 12 base pairs spanning the exon‒intron junction of the alternative exon 1 of the skin-specific SMARCAD1 isoform. In conclusion, we report two additional families with Basan syndrome and describe two SMARCAD1 pathogenic variants.

Background Polysensitivity is defined as three or more positive patch test reactions. The role of filaggrin gene (FLG) loss-of-function mutations in patients with polysensitivity has not been studied when barrier bypass and possible preceding barrier damage have been excluded. Objectives To determine whether FLG loss of function mutations play a role in patients with multiple contact sensitivities when barrier bypass is excluded. Methods One hundred and sixty-nine patients with three or more, non-cross-reacting, positive patch test reactions were prospectively enrolled in this study. Exclusion criteria were a history of hand dermatitis, nickel and metal implants, and stasis dermatitis. Subjects were patch tested with the North American extended patch test series, and with other relevant haptens. DNA was obtained and sequenced for the following FLG loss-of-function mutations: R501X, 2282del4, R2447X, and S3247X. Results One hundred and sixty-five patients were genotyped for the four FLG mutations. There was a significant association between R501X mutation and polysensitivity. For the other three tested mutations, there were no significant associations with polysensitivity. When all mutations were combined, there was a significant association between loss-of-function FLG mutations and polysensitivity in patients with a history of atopic dermatitis. Conclusion When skin barrier bypass is excluded, there is a significant association between polysensitivity and FLG loss-of-function mutations.

The CAG repeat polymorphism of the androgen receptor gene has been associated with an increased prostate cancer risk, and the repeat length correlated with cancer stage and grade at presentation. Men with an allele length of/= 18 CAG repeats have a 2-fold increase in risk for high-stage or high-grade prostate cancer, compared with patients with a longer CAG repeat. We examined the significance of the CAG repeat polymorphism of the androgen receptor gene for predicting prostate cancer progression among 318 patients treated by radical prostatectomy for clinically localized prostate cancer between 1987 and 1994.Leukocyte DNA was collected and genotyping of the CAG repeat polymorphism was performed using a PCR-based direct sequencing method. Risk ratios were calculated for developing biochemical recurrence for patients associated with an allele length of/= 18 CAG repeats, compared with patients with an allele length of18 CAG repeats, controlling for grade, stage and serum PSA level at diagnosis using Cox proportional hazard modeling.Overall, the CAG repeat allele was not predictive of recurrence; tumor grade, stage and PSA level at diagnosis were the only predictors of recurrence in a multivariate analysis. However, for patients at low risk for recurrence (Gleason score 2 to 6, stage pT2, and PSA/= 10 ng./ml.), the relative risk of recurrence associated with an allele of/= 18 CAG repeats was 8.07 (95% C.I., 2.02 to 32.2, p = 0.004), compared with patients with an allele length of18 CAG repeats. In contrast, for patients at high risk of recurrence (Gleason score/= 7, stage pT3/4, or PSA10 ng./ml.), the relative risk associated with the/= 18 CAG repeat allele was 0.72 (95% C.I., 0.33 to 1.57, p = 0.41), compared with patients with the18 CAG repeat allele.The length of the CAG repeat polymorphism of the androgen receptor gene may be important for prostate cancer recurrence among patients who are otherwise at low risk for recurrence after radical prostatectomy. These findings have potential implications for patient selection for adjuvant treatment, and for the development of novel treatments.

The hereditary breast and ovarian cancer syndrome is associated with a high frequency of BRCA1 mutations. However, the widespread use of BRCA1 testing has been limited to date by three principal concerns: the fear of loss of health and life insurance, the uncertain clinical value of a positive test result, and the current lack of an inexpensive and sensitive screening test for BRCA1 mutations. We have developed an inexpensive system for gene mutational scanning, based on a combination of extensive multiplex PCR amplification and two dimensional electrophoresis. The efficiency of this system, as a screening test for BRCA1 mutations, was evaluated in a panel of 60 samples from high risk women, 14 of which contained a previously identified mutation in BRCA1. All 14 mutations were identified, as well as an additional five that had previously escaped detection. In addition to the 19 mutations, a total of 15 different polymorphic variants were scored, most of which were recurring. All were confirmed by nucleotide sequencing. The cost of screening per sample was calculated to be approximately US$70 for the manual technique used in this study, and may be reduced to approximately US$10 with the introduction of commercially available PCR robotics and fluorescent imaging. Implementation of this method of mutation screening in the research and clinical setting should permit rapid accrual of quantitative data on genotype-phenotype associations for the evaluation of diagnostic testing. Keywords: genetic testing; two dimensional gene scanning (TDGS)