Characterization of a New Variant in ARHGAP31 Probably Involved in Adams-Oliver Syndrome in a Family with a Variable Phenotypic Spectrum.

Adams-Oliver syndrome is a rare inherited condition characterized by scalp defects and limb abnormalities. It is caused by variants in different genes such as ARHGAP31. Here, we used an interdisciplinary approach to study a family with lower limb anomalies. We identified a novel variant in the ARHGAP31 gene that is predicted to result in a truncated protein with a constitutively activated catalytic site due to the loss of 688 amino acids involved in the C-terminal domain, essential for protein auto-inhibition. Pathogenic variants in ARHGAP31 exon 12, leading to a premature protein termination, are associated with Adams-Oliver syndrome. Bioinformatic analysis was useful to elucidate the impact of the identified genetic variant on protein structure. To better understand the impact of the identified variant, 3D protein models were predicted for the ARHGAP31 wild type, the newly discovered variant, and other pathogenetic alterations already reported. Our study identified a novel variant probably involved in Adams-Oliver syndrome and increased the evidence on the phenotypic variability in patients affected by this syndrome, underlining the importance of translational research, including experimental and bioinformatics analyses. This strategy represents a successful model to investigate molecular mechanisms involved in syndrome occurrence.

Implementing Pre-Therapeutic UGT1A1 Genotyping in Clinical Practice: A Real-Life Study.

Current guidelines recommend pre-therapeutic UGT1A1 genotyping to guide irinotecan dosing, but the usefulness of this approach remains to be clarified. In 247 patients with advanced gastrointestinal cancers undergoing irinotecan-based chemotherapy, we prospectively performed UGT1A1*28 genotyping and we analyzed the incidence of severe neutropenia according to genotype-guided dose reductions. Overall, 28 (11.3%) and 92 (37.2%) patients were homozygous or heterozygous UGT1A1*28 carriers, respectively. Grade ≥ 3 neutropenia was reported in 39% of homozygous patients receiving an upfront dose reduction of irinotecan (median 40%, range 22-58%), in 20% of heterozygous or wild-type patients receiving full dose (ORvs*28/*28 genotype = 0.38; 95% CI: 0.14-1.03; p = 0.058), and in 15.3% of those receiving a reduced dose for clinical reasons (OR vs*28/*28 genotype = 0.28, 95% IC: 0.12-0.67; p = 0.004). Occurrence of severe neutropenia was inversely associated with dose reduction in UGT1A1*28 homozygous carriers (ORx10 unit = 0.62, 95% CI: 0.27-1.40, p = 0.249) and UGT1A1 heterozygous or wild-type patients (ORx10 unit = 0.87, 95% CI: 0.59-1.28, p = 0.478). Incidence of severe neutropenia was related to irinotecan doses and UGT1A1 polymorphisms. Upfront irinotecan dose reductions do not reduce the burden of grade ≥ 3 neutropenia in UGT1A1*28 homozygous carriers.

A new case of myelodysplastic syndrome associated with t(3;3)(q21;q26) and inv(11)(p15q22).

INTRODUCTION: Myeloid malignancies are associated with a number of recurrent and sporadic rearrangements that may be oncogenic by ensuring growth advantage and/or increased survival. t(3;3)(q21;q26) has been recognized as a recurrent abnormality in myelodysplastic syndromes (MDS) with poor prognostic significance. Inversion of chr(11) engendering NUP98-DDX10 chimeric product is sporadic and usually associated with diseases with poor prognosis (therapy-related myeloid neoplasm). To date, these cytogenetic abnormalities have been described as isolated events. CASE DESCRIPTION: We report the first case of an 80-year-old man with high-risk MDS harboring a translocation t(3,3)(q21q26) jointly with an inv(11)(p15q22) detected by fluorescent in situ hybridization analysis and conventional cytogenetic techniques. CONCLUSION: A similar pattern of acquisition was never described before in MDS. The coexistence of two independent, high-risk oncogenic, rare events in the same clone suggests that there may be a functional constraint for synergy between the two events, leading to a proliferative advantage and suggests the utility of extended genotyping in myeloid malignancies.

Ten new cases of Balanced Reciprocal Translocation Mosaicism (BRTM): Reproductive implications, frequency and mechanism.

Chromosomal anomalies are well known to be an important cause of infertility, sterility and pregnancy loss. Balanced Reciprocal Translocation Mosaicism (BRTM) is an extremely rare phenomenon, mainly observed in subjects with a normal phenotype accompanied by reproductive failure. To date the mechanism of origin and the incidence of BRTM are poorly defined. Here we describe 10 new cases of BRTM. In 9 cases chromosome analysis revealed the presence of two different cell lines, one with a normal karyotype and the second with an apparently balanced reciprocal translocation. In the remaining case, both cell lines showed two different, but apparently balanced, reciprocal translocations. We document the clinical implications of BRTM, discuss its frequency in our referred population and suggest that carrier individuals might be more frequent than expected.

The Italian National External Quality Assessment Program in Cytogenetics: 4 years of activity (2013-2016) following the introduction of poor performance criteria.

BACKGROUND: Italian External Quality Assessment (IEQA) Program in Cytogenetics, established in 2001 by the Istituto Superiore di Sanità (ISS), covers both Constitutional and Oncohaematological diagnosis. In 2013, performance criteria were defined and adopted. In this paper, we present the data from the first 4 years of activity (2013-2016) following the introduction of performance criteria. METHODS: The enrollment is voluntary, fee-based and open to both public and private Italian laboratories. The scheme is annual and retrospective; a national panel of experts assess technical, analytical and interpretative performance. RESULTS: Overall, 95 distinct Italian laboratories participated in different Cytogenetics IEQA schemes over the 2013-2016 years and most of the laboratories took part in Constitutional diagnosis. General hospitals and local health centers represented 40% of the total participants and the percentage of laboratories from Northern Regions was more than 45% of total participants throughout the 4-year period. As regards the performance evaluation, on average, 11, 9 and 23% of participants were marked as poor performers in Prenatal, Postnatal and Oncohaematological schemes, respectively. With regard to critical errors, ISCN nomenclature in Prenatal and Postnatal schemes, and interpretation in Oncohaematological diagnosis, were identified as main issues. On the other hand, karyotype errors and inadequate analysis decreased strongly, over the 4 years, in Constitutional and Oncohaematological diagnosis, respectively. CONCLUSIONS: Our data show that the introduction of poor performance encourages laboratories to address critical issues, and the IEQA participation helps to improve quality in cytogenetic testing.

De novo balanced chromosome rearrangements in prenatal diagnosis.

OBJECTIVE: We surveyed the datasheets of 29 laboratories concerning prenatal diagnosis of de novo apparently balanced chromosome rearrangements to assess the involvement of specific chromosomes, the breakpoints distribution and the impact on the pregnancy outcome. METHOD: By means of a questionnaire, data on 269.371 analyses performed from 1983 to 2006 on amniotic fluid, chorionic villus and fetal blood samples were collected. RESULTS: A total of 246 balanced anomalies were detected at frequencies of 72% for reciprocal translocations, 18% for Robertsonian translocations, 7% for inversions and 3% for complex chromosome rearrangements. The total frequencies of balanced rearrangements were 0.09%, 0.08% and 0.05% on amniotic fluid, chorionic villus and fetal blood samples. CONCLUSION: A preferential involvement of chromosomes 22, 7, 21, 3, 9 and 11 and a less involvement of chromosomes X, 19, 12, 6 and 1 was observed. A nonrandom distribution of the breakpoints across chromosomes was noticed. Association in the location of recurrent breakpoints and fragile sites was observed for chromosomes 11, 7, 10 and 22, while it was not recorded for chromosome 3. The rate of pregnancy termination was about 20%, with frequencies decreasing from complex chromosomal rearrangements (33%), reciprocal translocations (24%) to inversions (11%) and Robertsonian translocations (3%).

Prenatal diagnosis of del(9)(p24): a sex reverse case.

BACKGROUND: We report on a fetus with sex reversal and del(9)(p24) consequent to a malsegregation of a maternal balanced complex translocation involving chromosomes 7, 9 and 11. METHODS: Fluorescence in situ hybridization (FISH) was performed in order to verify the presence of the SRY gene and the absence of DMRT1 and DMRT2 genes located in 9p24.3 region and frequently associated with sex reversal. RESULTS AND CONCLUSIONS: The prenatal karyotype revealed an unbalanced male fetus. The postmortem examination showed a malformed fetus with female external genitalia. Lack of DMRT1-2 genes established by FISH.