Mutations in the human GLI2 gene were first reported in association with defective anterior pituitary formation, pan-hypopituitarism, and forebrain anomalies represented by typical holoprosencephaly (HPE) and holoprosencephaly-like (HPE-L) phenotypes and postaxial polydactyly. Subsequent, anophthalmia plus orbital anomalies, heminasal aplasia, branchial arch anomalies and polydactyly have also been incorporated into the general phenotype. Here we described six Brazilian patients with phenotypic manifestations that range from isolated cleft lip/palate with polydactyly, branchial arch anomalies to semi lobar holoprosencephaly. Novel sequence variants were found in the GLI2 gene in patients with marked involvement of the temporomandibular joint (TMJ), a new clinical finding observed with mutations of this gene. Clinical, molecular and genetic aspects are discussed.

No abstract

We describe a Brazilian boy with semilobar holoprosencephaly, ectrodactyly, bilateral cleft of lip and palate, and severe mental retardation. The karyotype was normal and the screening for mutations in the genes SHH, TGIF, SIX3, GLI2, TP73L, and DHCR7 did not show any change. This rare condition was described previously in seven male patients. Clinical and genetic aspects are discussed.

Here we report on a Brazilian female patient with the clinical manifestations of the holoprosencephaly-like phenotype who also presented with a retroocular granuloma diagnosed as Langerhans cell histiocytosis in early infancy. Mutation analysis showed a missense mutation (G316D) in the exon 2 of SIX3 gene, which was predicted as damaged by the PolyPhen program. We discuss the clinical and genetic aspects of this unusual case.

10631 Background: Brazil has a highly admixed population with significant Southern European, African and Native American genetic ancestries. Approximately 75% of the population has two or more continental ancestries. Therefore, breast cancer polygenic risk scores (PRS) developed in predominantly European populations requires validation in the Brazilian population. Compared with genotyping arrays and whole genome sequencing, affordable and scalable whole exome sequencing (WES) allows genotyping of both rare and common variants in the targeted regions and imputation of common variants not directly captured. In this study we validate a previously developed 3820-variant PRS using WES in 15,490 Brazilians. Methods: The cohort consisted of 6,362 women with a history of breast cancer (mean age 49.6, stddev 11.6) and 9,128 unphenotyped adults as controls (mean age 41.6, stddev 13.3). WES were performed on germline DNA and variants were called and curated. Imputation was done using the 1000 Genomes Phase 3 reference panel for variants falling outside the WES captured regions. After excluding subjects with known pathogenic or likely pathogenic variants in BRCA1, BRCA2, PALB2, PTEN, or TP53, and first or second-degree relatives of the probands, 14,577 individuals remained in the final analysis (5,730 cases and 8,847 controls). We restricted PRS calculation to 2,893 of the original 3,820 variants with an estimated global imputation accuracy of 96%. Odds ratios (OR) were adjusted using the top 10 principal components. Results: The breast cancer PRS showed a highly significant correlation with cancer risk (p-value = 7.1e-81, OR = 1.43, 95% confidence interval (CI) = 1.38-1.48 per PRS standard deviation). Compared with women in the middle deciles, those in the highest 10% had an OR of 1.93, while those in the lowest 10% had an OR of 0.52 (Table). Conclusions: In this study we show that WES can capture 76% of the variants included in a previously developed and validated breast cancer PRS, and the calculated PRS is correlated with breast cancer risk in the admixed Brazilian population. This opens the door for clinical studies into the application of PRS in Brazil, particularly in women without mutations in breast cancer high-penetrance genes. In addition, our WES-based PRS strategy can be quickly, affordably, and seamlessly adopted by labs that already offer Hereditary Breast Cancer panels that use WES as a backbone. [Table: see text]