Cesare Danesino

Efficient direct chromosome analyses and enzyme determinations from chorionic villi samples in the first trimester of pregnancy

SummaryChorionic villi were obtained by an aspiration technique which proved to be the best of four alternative procedures. We report in detail the series of experiments which led to (1) successful, rapidly growing cell cultures practically free of maternal cell contamination (the use of hormone-supplemented Chang medium greatly increased the growth rate);(2) an efficient direct method to obtain high quality metaphases from the Langhans cells of the cytotrophoblast tissue and with which the fetal karyotype is defined within a few hours of chorionic villi sampling; and (3) successful testing for the activity of eight enzymes directly from the villi samples, thus showing that this material is suitable for a rapid, direct diagnosis of the related metabolic diseases.

Genotype-phenotype correlations in hereditary hemorrhagic telangiectasia: Data from the French-Italian HHT network

Purpose: Hereditary hemorrhagic telangiectasia is an autosomal dominant disorder characterized by arteriovenous malformations (AVM), mostly cutaneous and mucous (telangiectases), but also involving the lungs (PAVM), liver (HAVM) and brain (CAVM). We studied the relationship between the phenotype and genotype in patients with a proven mutation in either ENG (HHT1) or ACVRL1 (HHT2).Methods: Clinical features and their age of onset were compared between HHT1 and HHT2. The type of mutation was also analyzed. Clinical manifestations were distinguished from lesions found by screening.Results: Ninety-three HHT1 patients and 250 HHT2 patients were included. Epistaxis occurred later in HHT2, with incomplete penetrance (P < 0.0001). Symptomatic PAVMs were more frequent in HHT1 (34.4 vs. 5.2%, P < 0.001), as were cerebral abscesses (7.5 vs. 0.8%, P = 0.002). Gastrointestinal bleeding occurred more frequently in HHT2 (16.4 vs. 6.5%, P = 0.017). Symptomatic hepatic involvement was only seen in HHT2 patients. PAVMs were more frequently detected in asymptomatic HHT1 patients (54 vs. 12.8%, P < 0.0001). PAVMs and HAVMs were often family clustered in HHT1 and HHT2, respectively. Truncating mutations were associated with a higher frequency of epistaxis and telangiectasis, in HHT2.Conclusion: This study shows major differences between HHT1 and HHT2 phenotypes, which should be taken into account for future clinical studies.

Apparent preferential loss of heterozygosity at TSC2 over TSC1 chromosomal region in tuberous sclerosis hamartomas

To investigate the molecular mechanisms of tuberous sclerosis (TSC) histopathologic lesions, we have tested for loss of heterozygosity the two TSC loci (TSC1 and TSC2) and seven tumor suppressor gene‐containing regions (TP53, NF1, NF2, BRCA1, APC, VHL, and MLM) in 20 hamartomas from 18 TSC patients. Overall, eight angiomyolipomas, eight giant cell astrocytomas, one cortical tuber, and three rhabdomyomas were analyzed. Loss of heterozygosity at either TSC locus was found in a large fraction of the informative patients, both sporadic (7/14) and familial (1/4). Interestingly, a statistically significant preponderance of loss of heterozygosity at TSC2 was observed in the sporadic group (P < 0.01). Among the possible explanations considered, the bias in the selection for TSC patients with the most severe organ impairment seems particularly appealing. According to this view, a TSC2 defect might confer a greater risk for early kidney failure or, possibly, a more rapid growth of a giant cell astrocytoma. None of the seven antioncogenes tested showed loss of heterozygosity, indicating that the loss of either TSC gene product may be sufficient to promote hamartomatous cell growth. Finally, the observation of loss of heterozygosity at different markers in an astrocytoma and in an angiomyolipoma from the same patient might suggest the multifocal origin of the second‐hit mutation. Genes Chromosom Cancer 15:18–25 (1996).

Diagnostic application of first trimester trophoblast sampling in 100 pregnancies

SummaryThe results of the diagnostic application of first trimester trophoblast sampling in 100 pregnancies are reported in detail. Further improvement of the method for routine, direct chromosome analysis resulted in a technique which proved to be fast, simple, and efficient. We found that short-term incubation of villi permits the application of many experimental methods, such as visualization of sister chromatid exchanges and bromodeoxyuridine (BrdU) incorporation. Fetal karyotyping was successful in each of the 96 pregnancies in which fetal material was obtained from a total of 98 fetuses. There were 42 males and 56 females, and an abnormal chromosome constitution was found in 12 cases. Two trisomic fetuses were found among the eight pregnancies at risk for Duchenne muscular dystrophy, and this indicates that fetal sexing (which is achieved with our method in two hours) should not be performed without chromosome visualization. The results indicate a risk of 8% of an abnormal fetus for mothers aged 35 years or more, while the risk of failure of sampling and of spontaneous abortion after villi sampling were 4 and 6%, respectively. Enzyme determinations were performed in three pregnancies at risk for gangliosidosis GM1, Niemann-Pick disease, and Hurler syndrome. In this last case inconsistency between the results of the assay of iduronidase on chorionic villi and amniotic fluid cells was found. This unexplained error indicates the need for extensive characterisation in chorionic villi of the series of enzymes involved in metabolic diseases.

Familial clustering of Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is considered a non‐hereditary disorder. Evaluation of the few familial cases might provide insight into its aetiology and pathogenesis. We conducted a survey to identify familial LCH cases. Data on family history, zygosity assessment in twins, clinical and laboratory features, treatment outcome, and present status were collected. According to variable confidence for twins monozygosity assessment, we termed these pairs ‘presumed monozygotic’ (pMZ). Nine families had more than one affected relative: five with LCH‐concordant twin pairs, four with LCH in siblings or cousins. Three twin pairs not concordant for LCH were also studied. Overall, four of five pMZ twin pairs and one of three dizygotic (DZ) pairs were concordant for LCH. The pMZ twins had simultaneous and early disease onset (mean age 5.4 months); onset was at 21 months in the DZ pair. Clinical features were similar in the pMZ pairs. One pair of DZ twins had disseminated LCH. The three healthy twins (one pMZ, two DZ) remain asymptomatic 0.3, 5.9 and 4.7 years, respectively, after disease onset in their co‐twins. Of the two families with affected non‐twin siblings, one had known parental consanguinity and the other possible consanguinity. Potential consanguinity was also present in one of the two families with affected first cousins. Our data support high LCH concordance rates in pMZ twins and add the finding of LCH concordance in one of three dizygotic pairs studied. Taken together with our identification of LCH in siblings and first cousins from known or possibly consanguineous families, and with prior reports of three affected parent–child pairs, the data support a role for genetic factor(s) in LCH. The work‐up of newly diagnosed patients should include a careful, extensive family history and chromosome studies. When possible, constitutional and/or lesional DNA should be obtained for future study.

Hepatic vascular malformations in hereditary hemorrhagic telangiectasia: Doppler sonographic screening in a large family

BACKGROUND/AIMS The prevalence of hepatic vascular malformations in hereditary hemorrhagic telangiectasia has been estimated in the literature on clinical criteria, thus giving unreliable data. In our study the presence of hepatic vascular malformations in hereditary hemorrhagic telangiectasia was evaluated in a large Italian family by using Doppler sonography findings were compared to computed tomography and angiography results. Clinical features were related to the severity of hepatic vascular malformations. METHODS Seventy-three relatives were checked for the presence of signs of hereditary hemorrhagic telangiectasia. Abdominal Doppler ultrasonography was performed in all of them. Every subject with a positive Doppler ultrasonography for hepatic vascular malformations underwent abdominal computed tomography and celiac angiography. RESULTS Forty family members proved to be affected by hereditary hemorrhagic telangiectasia. Of these, hepatic vascular malformations were evidenced by Doppler ultrasonography in 13 females. Doppler ultrasongraphy demonstrated minimal hepatic vascular abnormalities in three subjects, moderate in three, and severe in seven. Doppler study was diagnostic for arteriovenous shunt with hepatic veins in seven cases and with portal vein in two. Computed tomography failed to demonstrate hepatic vascular malformations in two cases, while angiography confirmed the Doppler sonographic findings in all cases. Cholestasis was present in subjects with moderate and severe hepatic vascular malformations. CONCLUSIONS Doppler sonography is the ideal imaging technique to screen hereditary hemorrhagic telangiectasia affected families for hepatic vascular malformations. These malformations do not appear to be age-dependent, but sex-dependent. Cholestasis is the main clinical sign, and it seems to correlate with the severity of hepatic vascular derangement.

Angiotensin converting enzyme gene deletion allele is independently and strongly associated with coronary atherosclerosis and myocardial infarction.

OBJECTIVE--To investigate the association of the three angiotensin converting enzyme (ACE) genotypes, DD, ID, and II, with the occurrence or absence of coronary atherosclerosis and with myocardial infarction and hypertension. DESIGN--Cohort analysis study. SETTING--North-Italy reference centre. SUBJECTS--388 white Italian patients (281 males; mean age 60.7 (SD 12.5) years) with proven coronary atherosclerosis (n = 255) or with angiographically normal coronary arteries (n = 133). A further group of 290 healthy blood donors was tested for allele frequency comparison. INTERVENTIONS--ACE/ID polymorphism was analysed with polymerase chain reaction on DNA from white blood cells. MAIN OUTCOME MEASURES--Coronary atherosclerosis, myocardial infarction, hypertension. RESULTS--The D and I allele frequencies were respectively 0.63 and 0.37 in the overall healthy blood donor group and 0.66 and 0.34 in the overall study group. In the latter, univariate analysis showed (1) that coronary atherosclerosis (255 patients) was associated with the deletion allele, with an odds ratio (OR) of 5.78 for DD/II, P < 0.001, and 2.39 for ID/II, P = 0.006; and (2) that myocardial infarction (154 patients) was associated with the DD genotype (OR DD/II = 2.56, P = 0.007), but not with the ID genotype (OR DD/II = 1.96, P = 0.056). Finally, hypertension proved to be unrelated with the ACE genotype. The distribution between the three genotypes of known risk factors for coronary artery disease was similar. Logistic regression modelling, performed to test the association of the selected risk factors simultaneously with coronary atherosclerosis and myocardial infarction, showed that the deletion allele (whether DD or ID) was the strongest risk factor for atherosclerosis, and that the D allele was significantly associated with the risk of infarction (although to a lesser extent than with coronary atherosclerosis). CONCLUSION--ACE deletion polymorphism is strongly and independently associated with coronary atherosclerosis and, to a lesser extent, with myocardial infarction. As such, the results are analogous to what has already been reported in French white, Japanese, and Welsh coronary patients.

Six novel mutations in the PRF1 gene in children with haemophagocytic lymphohistiocytosis

Editor—The histiocytoses represent a heterogeneous group of disorders including both hereditary and sporadic forms. The familial form of haemophagocytic lymphohistiocytosis (HLH) was originally described by Farquhar and Claireaux1 in 1952. The main features of this disease are fever, hepatosplenomegaly, cytopenia, hypertriglyceridaemia, hypofibrinogenaemia, and central nervous system involvement.2 3 Haemophagocytosis is observed at presentation or later during the course of the disease in most patients. In 1991, the Histiocyte Society defined its diagnostic criteria4; however, the differential diagnosis of HLH from other disorders may remain problematical, especially in patients without familial recurrence. Linkage of the disease gene to an approximately 7.8 cM region between markers D9S1867 and D9S1790 at 9q21.3-22 was identified by homozygosity mapping in four inbred families with HLH of Pakistani descent.5 Also, linkage analysis of a group of 17 families with HLH indicated mapping of a locus linked to HLH to the proximal region of the long arm of chromosome 10 in the 10q21-22 region in 10 families but not in the remaining seven, providing evidence for genetic heterogeneity of this condition.6-9 While no further cases of HLH linked to the 9q21.3-22 locus have been reported, recently Stepp et al 10 identified nine different mutations, three nonsense and six missense, in the two coding exons of the perforin 1 gene ( PRF1 ) in a group of eight unrelated patients, providing the first evidence for a disease related to PRF1 .10Perforin is an important mediator of lymphocyte cytotoxicity in a pathway independent from the Fas mediated apoptotic machinery. Thus, PRF1 mutations may affect cellular cytotoxicity, resulting in impaired antiviral defence and dysregulation of the apoptotic mechanisms involved in regulation of the immune response.11 We report six novel mutations and also confirm three additional mutations which had been previously reported. …

Deletion of a 5-cM Region at Chromosome 8p23 Is Associated With a Spectrum of Congenital Heart Defects

BACKGROUND Cytogenetic evidence suggests that the haploinsufficiency of > or =1 gene located in 8p23 behaves as a dominant mutation, impairing heart differentiation and leading to a wide spectrum of congenital heart defects (CHDs), including conotruncal lesions, atrial septal defects, atrioventricular canal defects, and pulmonary valve stenosis. An 8p heart-defect-critical region was delineated, and the zinc finger transcription factor GATA4 was considered a likely candidate for these defects. We narrowed this region and excluded a major role of GATA4 in these CHDs. METHODS AND RESULTS We studied 12 patients (7 had CHD and 5 did not) with distal 8p deletions from 9 families by defining their chromosome rearrangements at the molecular level by fluorescent in situ hybridization and short-tandem repeat analysis. Subjects with 8p deletions distal to D8S1706, at approximately 10 cM from the 8p telomere, did not have CHD, whereas subjects with a deletion that included the more proximal region suffered from the spectrum of heart defects reported in patients with 8p distal deletions. The 5-cM critical region is flanked distally by D8S1706 and WI-8327, both at approximately 10 cM, and proximally by D8S1825, at 15 cM. Neither GATA4 nor angiopoietin-2 (ANGPT2; a gene in 8p23 involved in blood vessel formation) were found to be deleted in some of the critical patients. We also found that CHDs are not related to the parental origin of deletion. CONCLUSIONS Haploinsufficiency for a gene between WI-8327 and D8S1825 is critical for heart development. A causal relationship does not seem to exist between GATA4 and ANGPT2 haploinsufficiency and CHDs.

Overlapping spectra of SMAD4 mutations in juvenile polyposis (JP) and JP–HHT syndrome†

Juvenile polyposis (JP) and hereditary hemorrhagic telangiectasia (HHT) are clinically distinct diseases caused by mutations in SMAD4 and BMPR1A (for JP) and endoglin and ALK1 (for HHT). Recently, a combined syndrome of JP–HHT was described that is also caused by mutations in SMAD4. Although both JP and JP–HHT are caused by SMAD4 mutations, a possible genotype:phenotype correlation was noted as all of the SMAD4 mutations in the JP–HHT patients were clustered in the COOH‐terminal MH2 domain of the protein. If valid, this correlation would provide a molecular explanation for the phenotypic differences, as well as a pre‐symptomatic diagnostic test to distinguish patients at risk for the overlapping but different clinical features of the disorders. In this study, we collected 19 new JP–HHT patients from which we identified 15 additional SMAD4 mutations. We also reviewed the literature for other reports of JP patients with HHT symptoms with confirmed SMAD4 mutations. Our combined results show that although the SMAD4 mutations in JP–HHT patients do show a tendency to cluster in the MH2 domain, mutations in other parts of the gene also cause the combined syndrome. Thus, any mutation in SMAD4 can cause JP–HHT. Any JP patient with a SMAD4 mutation is, therefore, at risk for the visceral manifestations of HHT and any HHT patient with SMAD4 mutation is at risk for early onset gastrointestinal cancer. In conclusion, a patient who tests positive for any SMAD4 mutation must be considered at risk for the combined syndrome of JP–HHT and monitored accordingly.