Cryptic chromosome rearrangements in five patients, with normal and/or abnormal karyotypes, associated with mental retardation, autism and/or epilepsy, detected by BAC genome array-CGH.

This report describes the usefulness of the BAC genome array-CGH platform in the detection of cryptic rearrangements. We examined ten patients with normal and/or abnormal karyotypes and dysmorphic features, associated with mental retardation, autism and/or epilepsy. This approach led us to discover further cryptic chromosomal rearrangements, not previously detected by conventional cytogenetic procedures, and allowed us to better delineate genotype/phenotype correlation. Our experience shows the validity of the BAC platform as a reliable method for genome-wide screening of chromosomal aberrations in patient with idiopathic mental retardation and/or in association with autism and epilepsy.

A rapid sample method for HLA haplotype typization. A preliminary study on celiac patients.

AIM: The aim of the present work was to determine the human leukocyte (HLA) haplotype in 64 Sardinian patients affected with celiac disease, using a rapid and easy to apply sampling method that permits samples from blood drawing to be stored more easily. Numerous studies have demonstrated how the HLA system plays a very important role in immune system regulation, determining a link between this gene and a high number of pathologies including celiac disease. In fact a genetic susceptibility exists in celiac sprue, linked to HLA-DQB1*0201 and -DQB1*0302 genes which represent sierologic groups -DQ2 and -DQ8 whose early identification could be fundamental in obtaining a diagnosis of celiac disease. METHODS: To realize this study a collecting method of samples was developed through the brushing of oral mucosa, which is extremely less traumatic than the classic sampling method using blood drawing, and which also allows a long conservation period before sample analysis. Samples were later analyzed with Van Embden's DNA extraction method to extract the patient's DNA, on which we executed the Polymerase Chain Reaction (PCR). To obtain the HLA haplotype from each patient we used 8 specific primers that amplified the HLA-DQB1 allele in low-resolution. RESULTS: Out of the 64 patients we found 26 HLA-DQB1*02 homozygotes, 28 HLA-DQB1*02 heterozygotes and 10 negative samples for the HLA-DQB1*02 allele, thus confirming what had emerged from previous blood draws. CONCLUSION: These results show how the method we developed using oral brushing is a sure method to obtain samples for determining the HLA haplotype in extra-hospital areas. This could allow the use of this method to obtain early diagnosis for chronic pathologies linked to the HLA groups and for recognizing this genotype in extensive population studies.

A family with segregation of an unbalanced translocation (7;13) (q36;q32) in three patients with severe mental retardation, microcephaly and dysmorphic features, detected by subtelomere FISH: genetic counselling and prenatal diagnosis.

We report a Sardinian family in which three members showed a mental-retardation-microcephaly-multiple malformations syndrome resulting from an unbalanced translocation (7;13)(q36;q32) which led to subtelomeric trisomy 7q36qter and partial monosomy 13q32qter. The unbalanced translocation was transmitted by alternate segregation from a female and a male carriers of the balanced translocation. The three patients had severe mental retardation, microcephaly and multiple minor facial and fingers anomalies. Neuroimages showed brain atrophy, associated in two patients with partial agenesis of the corpus callosum. FISH with chromosome 13 and 7 specific painting probes and subtelomere specific probes was instrumental for defining and characterizing the chromosomal translocation. Extensive genetic counseling and prenatal diagnosis has been offered to all the members of the family.

Cri du chat mosaicism: an unusual case of partial deletion and partial deletion/ duplication of the short arm of chromosome 5, leading to an unusual cri du chat phenotype.

The Cri du Chat Syndrome (CdCS) is one of the most common deletion syndromes, involving the short arm of chromosome 5, with an incidence of 1 in 50.000 live births. The following are the characteristic features of this syndrome: microcephaly, hypertelorism, round face, micrognatia, epicanthic folds, prominent nasal bridge, hypotonia and severe psychomotor retardation. Patients also show a high pitched cry similar to the mewing of a cat. Deletions and duplications of chromosome 5p have been described in the literature. Mosaicism represents only 3% of this cytogenetic aberration. Up to date, only cases of de novo 5p mosaic anomalies involving two or three rearranged cell lines, with deletions and duplications, have been described. Herein, we report the first case of a patient affected by multiple congenital anomalies and a mosaicism, with two rearranged cell lines: one with a 5p deletion; the other with a 5p deletion/duplication. Our patient did not show the characteristic features described in patients with 5p duplications, but a phenotype compatible with the CdCS. Our case represents the first description of a mosaicism with deletion and deletion/duplication of a portion of the short arm of chromosome 5.

Frequency of the thiopurine S-methyltransferase alleles in the ancient genetic population isolate of Sardinia.

BACKGROUND: Thiopurine S-methyltransferase (TPMT) is an enzyme involved in the normal metabolic inactivation of thiopurine drugs. Patients with intermediate or no TPMT activity are at risk of toxicity after receiving standard doses of thiopurine drugs and it was shown that inter-individual differences in response to these drugs is largely determined by genetic variation at the TPMT locus. OBJECTIVE: This study was designed to investigate in the Sardinian population the frequency distribution of four of the most common variants accounting for TPMT deficiency and to conduct comparative analyses with other populations in order to obtain insights into the main factors that have shaped diversity at the TPMT locus in Sardinia. METHODS: DNA was extracted in 259 Sardinians and the frequencies of allelic variants of TPMT were determined using polymerase chain reaction-restriction fragment length polymorphism technique. RESULTS: Among the 259 Sardinians genotyped, 6.95% were found to be heterozygous for one of four TPMT variants screened; for each variant the frequency estimate was 1.74%, 0.58%, 0.39% and 0.77% for TPMT*2, TPMT*3A, TPMT*3B and TPMT*3C respectively. CONCLUSIONS: Although Sardinia does not show reduced diversity at the TPMT locus, the spectrum of TPMT allele frequencies affords evidence of remarkable influence of genetic drift and founder effects throughout its population history. In the broad context of the European TPMT diversity, the Sardinians come out as outliers, an observation consistent with previous genetic inferences that Sardinia has features of a genetic isolate.

Duplication of the terminal band of the long arm of chromosome 7: a new case.

We report on a new case of de novo duplication of the terminal band of chromosome 7, 46, XX dup(7) (q36 > qter), defined by fluorescence in situ hybridization (FISH), which cause a recognizable phenotype consisting of macrocephaly, prominent frontal bossing, slight developmental delay.

Partial proximal trisomy 10q syndrome: a new case.

We report a case of partial proximal trisomy of the long arm of chromosome 10 confirmed by fluorescence in situ hibridization (FISH) performed with whole chromosome 10 specific painting and specific yac clones. The phenotypic findings, compared to those found in other published cases with the same karyotype, support the recognition of a distinctive partial proximal trisomy 10q syndrome (10q11-->q22).

X-linked mental retardation and characteristic physical features in two brothers with duplication Xp22-Xpter.

Two brothers are reported who share mental retardation, conjunctival teleangectasias (mainly equatorial) and characteristic flat face with small mouth and thin prolabia. At the neuropsychological examination, the older brother at 14 years showed a full scale IQ of 40 (WISC), with verbal IQ 45 and performance IQ 44. The younger brother at 7 years showed a full scale IQ of 58 (WPPSI), with verbal IQ 67 and performance IQ 55. Chromosome studies showed a duplication Xp22-Xpter in both brothers and in the inactivated X of their mother. The anomaly was not present in a 3rd healthy brother and in other healthy relatives. The mother has normal intelligence and did not present any of the physical features of her affected sons.

Pseudomosaic centric fission of chromosome 4 in amniotic cells.

This paper describes a case of pseudomosaic centric fission of chromosome 4 detected in amniotic fluid cell culture. The pregnancy went to term and the newborn had a normal chromosomal constitution.

Acute lymphoblastic leukemia in a child with constitutional ring chromosome 21.

This report describes a case of acute lymphoblastic leukemia with non-B, non-T, common acute lymphocytic leukemia antigen-positive blasts in a 13-year-old child with constitutional ring chromosome #21. Because ring chromosome #21 is a rare chromosomal disorder, it is likely that the leukemia transformation is related to the chromosomal anomaly.

Methyl-prednisolone treatment of serum HBsAg negative chronic active hepatitis occurring in transfusion-dependent thalassemia major.

We report the results of a two-year non randomized prednisolone trial carried out in 18 thalassemia major patients with chronic active hepatitis and in 16 controls. We found a beneficial effect on the biochemical remission rate and on the extent of liver inflammation with no significant side effects and no overt reactivation of possible latent HBV infection at three-year follow-up. However, a more prolonged longitudinal study is necessary in order to evaluate whether steroid treatment can impede the evolution to cirrhosis without determining long-term consequences, depending on virus-host interactions such as liver cell carcinoma.

Effect of subcutaneous desferrioxamine on iron balance in young thalassemia major patients.

In this study we evaluated the effect of 1-year, subcutaneous desferrioxamine daily infusion on iron balance in 23 thalassemia major children, aged 8-74 months, with transfusional iron accumulation less than 3.8 g at the outset of the trial. Statistical analysis showed a significant correlation between transfusional iron accumulation and percentage of transfusional iron eliminated. Confidence limits analysis of these data indicated that over 3.5 g of transfusional iron load, 95% of the patients may achieve balance. The appropriate time to begin desferrioxamine infusion, therefore, seems to be after about 30 transfusions of packed red blood cells when iron accumulation of approximately 3 g is reached. As we found a statistically significant correlation between transfusional iron eliminated and serum ferritin levels, the evaluation of serum ferritin alone can also predict when balance can be obtained.

Iron chelation in transfusion-dependent thalassemia with chronic hepatitis.

In this study maximum urinary iron elimination with continuous desferrioxamine subcutaneous infusion was obtained in thalassemia major patients with chronic persistent or active hepatitis with lower doses (60 mg/kg) than those necessary in patients without hepatitis (80 mg/kg). Since dose-response curves were highly variable the treatment schedule should be tailored to the individual needs of each patient. Both groups may achieve iron balance but chronic hepatitis patients have more frequently a net urinary iron excretion. In patients with chronic hepatitis no correlation was found between serum ferritin levels or serum ferritin/aspartate aminotransferase ratios and transfusional iron overload while serum ferritin/aspartate aminotransferase ratios were seen to be correlated with liver iron stores.

Iron overload and desferrioxamine chelation therapy in beta-thalassemia intermedia.

This study on serum ferritin levels in urinary iron excretion after 12h subcutaneous infusion of desferrioxamine in 10 thalassemia intermedia patients shows that even nontransfusion-dependent patients may have positive iron balance resulting in iron overload from 5 years of age. However, the iron overload found in these patients appears to be much lower than in age matched patients with transfusion-dependent thalassemia major. Iron overload increases with advancing age, as shown by increasing serum ferritin levels and desferrioxamine-induced urinary iron elimination. After a six month trial of 12h continuous subcutaneous desferrioxamine administration there was a significant decline in serum ferritin levels. From this study it seems that iron chelation is indicated in thalassemia intermedia patients over 5 years of age in order to prevent iron accumulation. However, the appropriate treatment schedule should be tailored to the individual needs of each patients, established by close monitoring of serum ferritin levels and desferrioxamine-induced urinary iron elimination.