A genotype-phenotype correlation in Sicilian patients with GJB2 biallelic mutations.

The aim of this work was to study the genotype distribution of Sicilian patients with biallelic GJB2 mutations; to correlate genotype classes and/or specific mutations of GJB2 gene (35delG-non-35delG) with audiologic profiles. A total of 10 different mutations and 11 different genotypes were evidenced in 73 SNHL subjects; 35delG (90.36 % of cases) and IVS1+1 (13.69 %) were the most common mutations found in the cohort with a significant difference in the distribution between North and South Sicily. Audiological evaluation revealed a severe (16/73) to profound (47/73) hearing loss (HL) in 86.13 % of cases without significant difference between the degree of HL and the province of origin of the subjects (P = 0.727). The homozygous truncating (T/T) genotype was the most widespread (89.04 % of cases), with a severe-to-profound hearing impairment in 90.36 % of T/T class with respect to truncating/non-truncating (T/NT) and non-truncating/non-truncating (NT/NT) genotypes (P = 0.012). From the comparison of homozygous 35delG and 35delG/non-35delG genotypes, a more profound HL in the homozygous 35delG than in compound heterozygous 35delG/non-35delG (p < 0.0001) resulted. This study confirms that 35delG is the most common mutation in the Mediterranean area with a heterogeneous distribution of the genotypes between North and South Sicily; probands homozygotes for 35delG or presenting a T/T genotype are more apt to have a severe-to-profound HL.

Identification of D179H, a novel missense GJB2 mutation in a western Sicily family.

The main purpose of this study was to describe a novel missense mutation (p.D179H) found in a Western Sicily family and to examine the genetic and audiologic profiles of all family members by performing a GJB2 and GJB6 mutations analysis and a complete audiologic assessment. The proband was a 3-month-old infant with a congenital profound sensorineural hearing loss; direct sequencing of the GJB2 revealed the presence of a c.35delG mutation in the heterozygous state and a heterozygous G>C transition at nucleotide 535 in trans; this novel mutation, called p.D179H, resulted in an aspartic acid to histidine change at codon 179. It was also evidenced in the heterozygous state in two members of this family, both with normal hearing. No GJB6 mutations were evidenced in all subjects studied. Considering the genotypic and phenotypic analysis of all family members, we suggest, differently from the p.D179 N mutation previously reported, a recessive mode of inheritance. Functional studies on p.D179H have to be performed to confirm our hypothesis.

Distribution and phenotype of GJB2 mutations in 102 Sicilian patients with congenital non syndromic sensorineural hearing loss.

OBJECTIVE: To evaluate the frequency of GJB2 mutations and their correlation with phenotype in Sicilian non-syndromic sensorineural hearing loss (NSHL) patients. DESIGN: Sequencing of the coding region, basal promoter, exon 1, and donor splice site of the GJB2 gene; screening for the presence of the two common GJB6 deletions. STUDY SAMPLE: A cohort of 102 Sicilian NSHL patients. RESULTS: Fifteen different mutations in GJB2 and seventeen different genotypes were detected. No GJB6 mutations were found. The hearing impairment was profound in the 64.72% of probands (mean PTA0.25-4 kHz of 88.82 ± 26.52 dB HL). A total of 81.37% of patients harboured at least one c.35delG allele; c.167delT and c.-23 + 1G> A were identified in 10.78% and the 9.8% of patients respectively; c.35delG homozygotes presented more severe hearing impairment (75.59% of profound hearing loss) and a higher mean PTA0.25-4 kHz (96.79 ± 21.11 dB HL) with respect to c.35delG/non-c.35delG and c.35delG/Wt patients (P < 0.05). CONCLUSIONS: This work underlines the role of c.35delG, c.167delT and c.-23 + 1G> A as the most frequent causes of NSHL in Sicily. The c.35delG frequency found is similar to those reported in other populations of the Mediterranean area. The analysis of genetic and audiologic data confirmed a variability in the phenotype associated to a single genotype.

Persistent jaundice in an infant with homozygous beta thalassemia due to co-inherited Crigler-Najjar syndrome.

Clinically apparent jaundice is unusual in patients with beta-thalassemia major. Co-inheritance of Gilbert syndrome has been reported to cause hyperbilirubinemia in these subjects. Crigler-Najjar syndrome is another rare disorder of bilirubin metabolism caused by mutation in the gene coding the enzyme UGT1A1. We report a patient of beta-thalassemia major who presented with persistent jaundice due to co-inherited Crigler-Najjar syndrome type 2 secondary to a novel mutation in UGT1A1 gene [homozygous base substitution at position 362 (GGT>AGT) in exon 3].

Thrombophilic Genetic Factors PAI-1, MTHFRC677T, V Leiden 506Q, and Prothrombin 20210A in Noncirrhotic Portal Vein Thrombosis and Budd-Chiari Syndrome in a Caucasian Population.

Thrombophilic genetic factors PAI-1, MTHFRC677T, V Leiden 506Q, and Prothrombin 20210A were studied as risk factors in 235 Caucasian subjects: 85 patients with abdominal thrombosis (54 with portal vein thrombosis (PVT) and 31 with Budd-Chiari syndrome (BCS) without liver cirrhosis or hepatocellular carcinoma) and 150 blood bank donors. Seventy-five patients with PVT/BCS showed associated disease or particular clinical status (46 PVT/29 BCS): 37 myeloproliferative neoplasm (20 PVT/17 BCS), 12 abdominal surgery (10 PVT/2 BCS), 10 contraception or pregnancy (6 PVT/4 BCS), 7 abdominal acute disease (6 PVT/1 BCS), and 9 chronic disease (4 PVT/5 BCS); ten patients did not present any association (8 PVT/2 BCS). PAI-14G-4G, MTHFR677TT, and V Leiden 506Q were significantly frequent (OR 95% CI and χ (2) test with P value) in abdominal thrombosis; in these patients PAI-14G-4G and MTHFR677TT distributions deviated from that expected from a population in the Hardy-Weinberg equilibrium (PAI-1: χ (2) = 13.8, P < 0.001; MTHFR677: χ (2) = 7.1, P < 0.01), whereas the equilibrium was respected in healthy controls. V Leiden Q506 and Prothrombin 20210A were in the Hardy-Weinberg equilibrium both in patients with abdominal thrombosis and healthy controls. Our study shows an important role of PAI-14G-4G and MTHFR677TT in abdominal thrombosis without liver cirrhosis or hepatocellular carcinoma.