Sex-specific effect of P2Y2 purinergic receptor on glucose metabolism during acute inflammation.

The sex of an animal impacts glucose sensitivity, but little information is available regarding the mechanisms causing that difference, especially during acute inflammation. We examined sex-specific differences in the role of the P2Y2 receptor (P2Y2R) in glucose flux with and without LPS challenge. Male and female wild-type and P2Y2R knockout mice (P2Y2R-/-) were injected with LPS or saline and glucose tolerance tests (GTT) were performed. P2Y2R, insulin receptor, and GLUT4 transporter gene expression was also evaluated. Female mice had reduced fasting plasma glucose and females had reduced glucose excursion times compared to male mice during GTT. P2Y2R-/- males had significantly decreased glucose flux throughout the GTT as compared to all female mice. Acute inflammation reduced fasting plasma glucose and the GTT area under the curve in both sexes. While both wild-type and P2Y2R-/- male animals displayed reduced fasting glucose in LPS treatment, female mice did not have significant difference in glucose tolerance, suggesting that the effects of P2Y2R are specific to male mice, even under inflammatory conditions. Overall, we conclude that the role for the purinergic receptor, P2Y2R, in regulating glucose metabolism is minimal in females but plays a large role in male mice, particularly in the acute inflammatory state.

Genome sequencing identifies coding and non-coding variants for non-syndromic hearing loss.

Hearing loss (HL) is a common heterogeneous trait that involves variants in more than 200 genes. In this study, we utilized exome (ES) and genome sequencing (GS) to effectively identify the genetic cause of presumably non-syndromic HL in 322 families from South and West Asia and Latin America. Biallelic GJB2 variants were identified in 58 probands at the time of enrollment these probands were excluded. In addition, upon review of phenotypic findings, 38/322 probands were excluded based on syndromic findings at the time of ascertainment and no further evaluation was performed on those samples. We performed ES as a primary diagnostic tool on one or two affected individuals from 212/226 families. Via ES we detected a total of 78 variants in 30 genes and showed their co-segregation with HL in 71 affected families. Most of the variants were frameshift or missense and affected individuals were either homozygous or compound heterozygous in their respective families. We employed GS as a primary test on a subset of 14 families and a secondary tool on 22 families which were unsolved by ES. Although the cumulative detection rate of causal variants by ES and GS is 40% (89/226), GS alone has led to a molecular diagnosis in 7 of 14 families as the primary tool and 5 of 22 families as the secondary test. GS successfully identified variants present in deep intronic or complex regions not detectable by ES.

Experiences of the Molecular Diagnosis of Fragile X Syndrome in Ecuador.

Fragile X syndrome (FXS) is the most common cause of hereditary intellectual disability and the second most common cause of intellectual disability of genetic etiology. This complex neurodevelopmental disorder is caused by an alteration in the CGG trinucleotide expansion in fragile X mental retardation gene 1 (FMR1) leading to gene silencing and the subsequent loss of its product: fragile X mental retardation protein 1 (FMRP). Molecular diagnosis is based on polymerase chain reaction (PCR) screening followed by Southern blotting (SB) or Triplet primer-PCR (TP-PCR) to determine the number of CGG repeats in the FMR1 gene. We performed, for the first time, screening in 247 Ecuadorian male individuals with clinical criteria to discard FXS. Analysis was carried out by the Genetics Service of the Hospital de Especialidades No. 1 de las Fuerzas Armadas (HE-1), Ecuador. The analysis was performed using endpoint PCR for CGG fragment expansion analysis of the FMR1 gene. Twenty-two affected males were identified as potentially carrying the full mutation in FMR1 and thus diagnosed with FXS that is 8.1% of the sample studied. The average age at diagnosis of the positive cases was 13 years of age, with most cases from the geographical area of Pichincha (63.63%). We confirmed the familial nature of the disease in four cases. The range of CGG variation in the population was 12-43 and followed a modal distribution of 27 repeats. Our results were similar to those reported in the literature; however, since it was not possible to differentiate between premutation and mutation cases, we can only establish a molecular screening approach to identify an expanded CGG repeat, which makes it necessary to generate national strategies to optimize molecular tests and establish proper protocols for the diagnosis, management, and follow-up of patients, families, and communities at risk of presenting FXS.