DPYD*6 plays an important role in fluoropyrimidine toxicity in addition to DPYD*2A and c.2846A>T: a comprehensive analysis in 1254 patients.

Dihydropyrimidine dehydrogenase (DPYD) is a highly polymorphic gene and classic deficient variants (i.e., c.1236G>A/HapB3, c.1679T>G, c.1905+1G>A and c.2846A>T) are characterized by impaired enzyme activity and risk of severe adverse drug reactions (ADRs) in patients treated with fluoropyrimidines. The identification of poor metabolizers by pre-emptive DPYD screening may reduce the rate of ADRs but many patients with wild-type genotype for classic variants may still display ADRs. Therefore, the search for additional DPYD polymorphisms associated with ADRs may improve the safety of treatment with fluoropyrimidines. This study included 1254 patients treated with fluoropyrimidine-containing regimens and divided into cohort 1, which included 982 subjects suffering from gastrointestinal G≥2 and/or hematological G≥3 ADRs, and cohort 2 (control group), which comprised 272 subjects not requiring dose reduction, delay or discontinuation of treatment. Both groups were screened for DPYD variants c.496A>G, c.1236G>A/HapB3, c.1601G>A (DPYD*4), c.1627A>G (DPYD*5), c.1679T>G (DPYD*13), c.1896T>C, c.1905 + 1G>A (DPYD*2A), c.2194G>A (DPYD*6), and c.2846A>T to assess their association with toxicity. Genetic analysis in the two cohorts were done by Real-Time PCR of DNA extracted from 3 ml of whole blood. DPYD c.496A>G, c.1601G>A, c.1627A>G, c.1896T>C, and c.2194G>A variants were found in both cohort 1 and 2, while c.1905+1G>A and c.2846A>T were present only in cohort 1. DPYD c.1679T>G and c.1236G>A/HapB3 were not found. Univariate analysis allowed the selection of c.1905+1G>A, c.2194G>A and c.2846A>T alleles as significantly associated with gastrointestinal and hematological ADRs (p < 0.05), while the c.496A>G variant showed a positive trend of association with neutropenia (p = 0.06). In conclusion, c.2194G>A is associated with clinically-relevant ADRs in addition to the already known c.1905+1G>A and c.2846A>T variants and should be evaluated pre-emptively to reduce the risk of fluoropyrimidine-associated ADRs.

Gene editing of DNAH11 restores normal cilia motility in primary ciliary dyskinesia.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare autosomal recessive genetic disorder characterised by dysfunction of motile cilia. Ciliary dysmotility causes poor mucociliary clearance and leads to impairment of pulmonary function and severe respiratory infections. PCD has no specific therapy. With the aim to permanently restore gene function and normalise ciliary motility, we used gene editing to replace mutated with wild-type sequence in defective cells. METHODS: The target gene was dynein heavy chain 11 (DNAH11), an essential component of ciliary structure. Airway ciliated cells were collected from two patients with PCD with DNAH11 nonsense mutations and altered ciliary beating and pattern. Repair of the genetic defect was performed ex vivo by site-specific recombination using transcription activator-like effector nucleases (TALENs). RESULTS: In an epithelial cell line engineered to contain the DNAH11 target site, TALENs cleaved over 80% of the mutated DNAH11 sequence and replaced the mutated sequence with wild-type sequence in about 50% of cells. In airway ciliated cells of patients with PCD, site-specific recombination and normalisation of ciliary beating and pattern occurred in 33% and 29% of cells, respectively. CONCLUSION: This study demonstrates that gene editing can rescue ciliary beating ex vivo, opening up new avenues for treating PCD.

625 kb microduplication at Xp22.12 including RPS6KA3 in a child with mild intellectual disability.

Here, we report on a patient with a 625 kb duplication in Xp22.12, detected by array comparative genomic hybridization (CGH). The duplicated region contains only one gene, RPS6KA3, that results in partial duplication. The same duplication was present in his mother and his maternal uncle. This partial duplication inhibits the RPS6KA3 expression, mimicking the effect of loss-of-function mutations associated with Coffin-Lowry syndrome (CLS). The phenotype of the patient here presented is not fully evocative of this syndrome because he does not present some of the facial, digital and skeletal abnormalities that are considered the main diagnostic features of CLS. This case is one of the few examples where RPS6KA3 mutations are associated with a non-specific X-linked mental retardation.

Acro-cardio-facial syndrome: a microdeletion syndrome?

Acro-cardio-facial syndrome (ACFS) is an infrequently reported, variable condition characterized by split-hand and split-foot malformation and congenital heart defect (CHD), along with cleft lip and palate, genital anomalies, unusual face and intellectual disability. An autosomal recessive pattern of inheritance has been suggested because of affected sibs born to unaffected parents and parental consanguinity; the cause is unknown. We describe a newborn with the clinical manifestations of ACFS in whom a deletion of the region 6q21-q22.3 was detected by array CGH. We compare the clinical features of the present patient with earlier reported patients with similar 6q deletions and patients diagnosed with ACFS. The similarities between these patient groups suggest that ACFS may be a microdeletion syndrome caused by loss of the 6q21-22.3 region. The recurrence in families may be explained by prenatal germline mosaicism. Alternatively, ACFS may be a genetically heterogeneous disorder which can also be caused by biallelic mutations of an autosomal recessive gene.

Syndromic craniosynostosis due to complex chromosome 5 rearrangement and MSX2 gene triplication.

Craniosynostosis is a common birth defect ( approximately 1/3,000 births) resulting from chromosome imbalances, gene mutations or unknown causes. We report a 6-month-old female with multiple sutural synostosis and prenatal onset growth deficiency, developmental delay, facial dysmorphism, congenital heart defect, and inguinal hernia. An integrated approach of standard cytogenetics, mBAND, locus-specific FISH, and 75 kb resolution array-CGH disclosed a complex chromosome 5 rearrangement, resulting in 3 paracentric inversions, 2 between-arm insertions, and partial duplication of 5q35. An extra copy of the MSX2 gene, which maps within the duplicated segment and is mutated in Boston-type craniosynostosis, was confirmed by molecular cytogenetic studies. Our study confirms that early fusion of cranial sutures commonly observed in the dup(5q) syndrome is caused by triplication of the MSX2 gene and strongly supports the crucial role of this gene in the development of craniofacial structures.

Cytogenetic study of 435 subfertile men: incidence and clinical features.

OBJECTIVE: To evaluate the incidence of chromosomal anomalies in a series of unselected infertile men. STUDY DESIGN: Four hundred thirty-five consecutive, unselected men with a history of several years of infertility with or without sperm count anomalies and attending our center for karyotype analysis were included in this study. Peripheral blood metaphases were analyzed by standard G and Q banding. When required, fluorescence in situ hybridization and polymerase chain reaction for analysis of specific Y chromosome regions were performed. RESULTS: Twenty-three of 435 patients (5.2%) had an abnormal karyotype; 18 of these (4.1%) showed numerical or structural anomalies of the sex chromosomes and 5 (1.1%), anomalies of the autosomes. CONCLUSION: Our data confirm the importance of karyotype analysis in infertile men, especially in those with sperm anomalies. This analysis can provide useful information also for patients with long-term infertility and considering assisted reproduction techniques.

Uncommon dihydropyrimidine dehydrogenase mutations and toxicity by fluoropyrimidines: a lethal case with a new variant.

DPD is the rate-limiting enzyme involved in the metabolism of 5-fluorouracil and its prodrugs, capecitabine and tegafur. Many cases of severe toxicities by fluoropyrimidines are reported in the literature, sometimes with lethal outcome, due to a poor or null metabolizer phenotype. The exon 14-skipping mutation IVS14+1G>A and the c.2846A>T are the most common deficient variants. However, many additional variants of the DPYD gene with unclear functional significance have been reported. We describe a patient with metastatic breast cancer who received capecitabine and trastuzumab at standard doses. Six days after beginning capecitabine, the patient developed fever, leucopenia and neutropenia, mucositis, hand-foot syndrome, multiple organ dysfunction and eventually died. Since the toxicity profile was compatible with capecitabine administration, complete exon sequencing of DPYD was carried out and the patient was found to be compound heterozygous for the rare mutation c.257C>T in exon 4, c.496A>G in exon 6, the new variant c.1850C>T in exon 14 and c.2194G>A in exon 18. Given the marginal role of c.496A>G and c.2194G>A in DPD deficiency, the cause of death was suggested to be dependent on the novel c.1850C>T in combination with c.257C>T. The complexity of DPD pharmacogenetics suggests the need to develop cost-effective screening approaches to identify patients at risk of severe toxicities.

Quantitative molecular monitoring of BCR-ABL and MDR1 transcripts in patients with chronic myeloid leukemia during Imatinib treatment.

Different mechanisms could sustain Imatinib resistance, including overexpression of MDR1, a gene already known to be responsible for multidrug resistance in other hematologic malignancies. In search for a possible correlation, BCR-ABL and MDR1 expression were measured in 115 serial bone marrow samples from 33 CML patients during Imatinib treatment. All patients achieved complete hematologic responses, and 22 patients also achieved complete cytogenetic responses, with median BCR-ABL mRNA values significantly lower than those observed in the group of cases that were persistently Philadelphia positive. All three cases treated during the accelerated phase showed disease progression after an initial period of remission; all presented either increased levels of BCR-ABL or MDR1 3 months before clinical progression. In the subgroup of cases treated during the chronic phase, BCR-ABL and MDR1 levels were significantly correlated after 3 and 6 months (88 and 80%, respectively) but not after 12 months of treatment (32%). Reported data maintain that MDR1 expression would play an important role in Imatinib resistance when the disease is not fully controlled (e.g., progressive disease or during the first months of treatment).

A 46,XX SRY-negative man with complete virilization and infertility as the main anomaly.

OBJECTIVE: To report a case of a 46,XX SRY-negative man with a male phenotype and azoospermia. DESIGN: Case report. SETTING: Molecular and Cytogenetic Unit in a University Hospital. PATIENT(S): A 35-year-old man with complete masculinization who referred to our institution because of a history of several years of infertility. INTERVENTION(S): Lymphocytic karyotype and genetic counseling. MAIN OUTCOME MEASURE(S): Peripheral blood metaphases were analyzed by standard G-banding and Q-banding. Fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR) analyses were performed. RESULT(S): Semen analysis showed azoospermia. Chromosome analysis revealed a 46,XX karyotype; molecular and cytogenetic analyses excluded the presence of SRY (the sex-determining region of the Y chromosome) gene. CONCLUSION(S): This case is one of the rare patients reported in the literature in whom testicular differentiation and a complete virilization in a 46,XX chromosomal constitution does not account for a translocation of the SRY gene to the X chromosome or to the autosomes. This finding suggests that other genes downstream from SRY, not yet identified, play an important role in sex determination.

Discovery of novel mutations in the dihydropyrimidine dehydrogenase gene associated with toxicity of fluoropyrimidines and viewpoint on preemptive pharmacogenetic screening in patients.

BACKGROUND: Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme of the metabolic pathway of 5-fluorouracil (5-FU) and other fluoropyrimidines to inactive compounds. For this reason, severe, life-threatening toxicities may occur in patients with deficient DPD activity when administered standard doses of 5-FU and its prodrugs. MATERIALS AND METHODS: We selected three patients with colorectal adenocarcinoma who displayed unexpected severe adverse reactions after treatment with 5-FU and capecitabine. To investigate the possible involvement of deficient variants of the DPD gene (DPYD), a denaturing HPLC (dHPLC) approach followed by target exon sequencing of DPYD was performed on DNA extracted from peripheral blood. RESULTS: Three novel non-synonymous mutations of DPYD, c.2509-2510insC, c.1801G>C, and c.680G>A, were detected in these subjects. Due to the absence of other deficient variants of DPYD and the compatibility of adverse reactions with fluoropyrimidine treatment, the novel variants were associated with a poor-metabolizer phenotype. CONCLUSIONS: Stratification of patients on the basis of their genotype may help prevent toxicity, and the large body of evidence about the pathogenesis of fluoropyrimidine-induced adverse reactions strongly encourages the adoption of best practice recommendations to appropriately address this important clinical issue. This approach is of utmost importance within a preventive, prognostic, and personalized approach to patient care in the oncology setting.

Mannose-binding lectin 2 gene polymorphism and lung damage in primary ciliary dyskinesia.

BACKGROUND: Mannose-binding lectin (MBL) plays an important role in innate immunity and has been reported to be associated with the age-related decline in lung function in cystic fibrosis. HYPOTHESIS: MBL polymorphisms are associated with lung function decline in Primary Ciliary Dyskinesia (PCD). METHODS: We performed sputum microbiology, spirometry pre- and post-administration of salbutamol, ciliary motion analysis, ultrastructural assessment of cilia, ciliogenesis in culture, and chest high resolution computed tomography in children with a clinical history of respiratory tract infections and/or presence of bronchiectasis suggestive of PCD or secondary ciliary dyskinesia (SCD). All subjects were evaluated for single nucleotide polymorphisms in the gene encoding MBL-2. RESULTS: The diagnosis of PCD was established in 45 subjects, while in the remaining 53 the diagnosis was SCD. A significant bronchodilator response was observed only in PCD associated with the MBL2-3 genotype, which is known to be associated with low/undetectable MBL serum levels. Also, bronchiectasis severity was significantly greater in subjects with MBL2-3 in both PCD and SCD. No other association was found between MBL genotypes and clinical findings. CONCLUSIONS: MBL plays a relatively minor role as a disease modifier in PCD. A similar finding in SCD supports the likely significance of this result.

Molecular characterization of 22q11 deletion in a three-generation family with maternal transmission.

Haploinsufficiency of chromosome 22q11.2 is a well-established cause of both the DiGeorge anomaly and the velocardiofacial syndrome. This condition shows a continuous spectrum of phenotypic manifestations with a considerable inter- and intrafamilial variability. We report on a three-generation family with four members sharing the same 3 Mb long deletion but showing different phenotypic expression. In the first generation, the deleted patient has hypernasal speech and suffers from recurrent psychotic episodes. Two of her offspring inherited the deletion. One of these, a male, has hypernasal speech, low-set ears, hypocalcemia, severe development delay, and tetralogy of Fallot. The other, a female, has hypernasal speech, minor facial anomalies, and very mild mental retardation. Her daughter has tetralogy of Fallot, velopharyngeal insufficiency, and mild facial anomalies. This family is an example of the widely variable phenotypic expressivity of the 22q11.2 deletion. There is no correlation between the size of the deletion and the phenotypic manifestations. Genetic background and/or environmental factors could explain the different phenotypes observed in the affected members of the family.

Molecular and cytogenetic characterization of a structural rearrangement of the Y chromosome in an azoospermic man.

OBJECTIVE: To better define an abnormal karyotype found in a male with primary infertility. DESIGN: Case report. SETTING: Molecular and cytogenetics unit in a university-affiliated hospital. PATIENT(S): A 41-year-old, azoospermic, but otherwise healthy male. INTERVENTION(S): Lymphocytic karyotype and genetic counseling. MAIN OUTCOME MEASURE(S): Metaphases were studied by standard G- and Q-banding, followed by fluorescence in situ hybridization (FISH) and polymerase chain reaction to analyze specific Y chromosome regions. RESULT(S): Chromosomal analysis and FISH allowed us to define the propositus's karyotype as 45,X/46,X,idic(Yp)/46,XY (71%, 26%, and 3% of analyzed metaphases, respectively). Molecular analysis of azoospermic factor (AZF) regions showed deletion of AZFb and AZFc. CONCLUSION(S): A 45,X/46,X,idic(Yp) mosaicism is associated with a very broad spectrum of phenotypes, including patients with Ullrich-Turner syndrome, patients with various degrees of genital ambiguity, or normal males. In the presence of a normal masculinization in otherwise healthy males azoospermia is a distinct feature that can be explained by partial deletion of AZF regions.

Regulation of telomerase and its hTERT messenger in colorectal cancer.

Telomeres are the distal ends of human chromosomes composed of tandem repeats of the sequence TTAGGG. In most human somatic cells, telomerase activity is undetectable, and the telomere length is progressively shortened during cell proliferation, leading to cellular senescence. In contrast, telomerase is activated in the vast majority of cancer cells, including colorectal cancer. The human telomerase complex is comprised of multiple components, but telomerase reverse transcriptase (hTERT) is the most important component for the control of telomerase activity. The p53 protein is a transcription factor with multiple biological activities, including cell cycle arrest and/or apoptosis upon DNA damage, hypoxia and oncogene activation; this requires transactivation or repression of specific target genes by wild-type p53. To better understand if a link between hTERT/telomerase regulation and p53 status exists in colorectal carcinogenesis, we analysed 43 cases of colorectal carcinoma for hTERT mRNA expression and telomerase activity. Moreover, a complete analysis of p53 status was performed. Alterations of p53 gene were found in 44.19% of cases and missense point mutations represented a high proportion of p53. Both telomerase activity (p=0.014) and hTERT expression (p=0.03) were significantly associated with p53 mutations, suggesting a role of p53 in the signaling pathway for telomerase control.

Homeobox HOXA10 gene analysis in cryptorchidism.

BACKGROUND: In male mice, targeted disruption of the homeobox gene hoxa10 causes cryptorchidism and infertility. Genetic alterations in exon 1 of HOXA10 have been found in a high number of boys with cryptorchidism. AIM: To evaluate whether mutations of HOXA10 can be a common cause of cryptorchidism. PATIENTS AND METHODS: Genomic DNA was extracted from 18 patients with cryptorchidism (age 7-44 years; unilateral n = 13; no familial cases) and 28 healthy controls (age 9-39 years). HOXA10 was amplified by PCR and all coding sequences of exon 1 and 2 were sequenced. The PCR products were digested by ScrFI restriction enzyme and the restriction fragments obtained were analyzed on 2% agarose gel. RESULTS: One silent polymorphism, G-->A substitution at position 1203, was detected in 2/18 patients (11.1%). The same polymorphism was detected in 3/28 controls (10.7%). CONCLUSIONS: These data on HOXA10 analysis indicate that alterations of this gene may be more rare in males with cryptorchidism than previously suggested. This finding agrees with the rare occurrence of INSL3 gene mutations in human cryptorchidism, but needs to be confirmed in a larger series of selected patients.

Growth and puberty in Turner's syndrome.

Turner's syndrome is the commonest sex chromosome abnormality in females, resulting from the absence of an X chromosome or the presence of a structurally abnormal X chromosome. Short stature and ovarian failure are the most consistent clinical features and require specific and co-ordinated medical approaches in order to improve final height and well-being in adulthood. High doses of growth hormone (GH) are able to improve adult height in comparison with untreated patients. GH therapy should be started during childhood as soon as the growth curve declines below the 5th percentile and doses adjusted according to clinical response. Some studies reported that combined therapy with GH and an anabolic steroid--oxandrolone--is also beneficial at lower GH doses. Ovarian failure should be treated by appropriate substitutive estrogen therapy. Since estrogen administration may impair growth of patients with Turner's syndrome, the age at beginning of therapy should be individualized taking into consideration potential growth, the need for feminization, bone mineral density and the psychological well-being of each patient. Well co-ordinated endocrine interventions can permit better long-term outcome in adulthood.