[Inherited disorders of bilirubin metabolism]

Jaundice in an infant or older child may reflect accumulation of either unconjugated or conjugated bilirubin and could be related to inherited bilirubin disorders. Three grades of inherited unconjugated hyperbilirubinemia are recognised in humans. This spectrum of disorders is distinguished primarily on the basis of the plasma bilirubin level, the response to phenobarbital administration, and the presence or absence of bilirubin glucoronides in bile. The enzyme responsible for the conjugation of bilirubin is the bilirubin uridine-diphosphate-glucuronosyltransferase (UGT). Mutations in the gene encoding bilirubin-UGT (UGT1A1), lead to complete or partial inactivation of the enzyme causing the rare autosomal recessively inherited conditions, Crigler-Najjar syndrome type 1 (CN-1) and type 2 (CN-2). Gilbert syndrome (GS) is due to an insertional mutation at homozygous state of the TATAA element (seven TA repeats) of UGT1A1 producing a reduced level of expression of the gene. The association of GS with haemolytic anemias, e.g., Hereditary Spherocytosis (HS) or Congenital Dyserythropoietic Anemia type 2 (CDA 2), increase the hyperbilirubinemia level and the risk of cholelithiasis. Forms of chronic conjugated hyperbilirubinemia are Dubin-Johnson syndrome, Rotor syndrome, Alagille syndrome or arteriohepatic dysplasia, Wilson disease or hepatolenticular degeneration. Liver or liver cell transplantation is the therapy in some cases.

Minimally invasive closure of patent foramen ovale through port-access surgery

We present here our experience of patent foramen ovale closure through a mini-invasive surgical technique. With the new surgical platform termed Heartport System, it is possible to install extra-corporeal circulation and to obtain cardioplegic arrest of the heart with endovascular techniques. This allows the operation of closure to be entirely performed through a micro-thoracotomy (Port-access surgery) in the right 4th intercostal space. Sixty-one patients underwent this surgical correction and seventeen of them (26%) had a diagnosis of patent foramen ovale, 12 with an history of cerebrovascular accidents. They are all alive and well after a mean follow-up of 16 months, with no recurrence of the inter-atrial communication and free from new neurological events. The post-operative course was uneventful with patients discharged on postoperative day 4. This technique shows a 100% efficacy, minimise surgical trauma, allows a quick recovery and offers excellent cosmetic results with no scarring. We believe that this procedure must be regarded as the "golden standard" for the closure of atrial septal defects

[Surgical complications following pancreaticoduodenectomy: results of a single center experience]

Pancreaticoduodenectomy represents the only therapeutic option for cefalo-pancreatic and periampullary cancers. Surgical and anaesthesiological techniques development over the last twenty years has granted an operative mortality decrease. However, surgical morbidity is still high, with an incidence of 30-50%. A 20 year experience of a single Centre is examined retrospectively: 121 patients underwent pancreatic resection with radical intent. Type of operation or re-operation, operative mortality within 30 days, general and surgical morbidity, postoperative hospital stay were analysed. Average recovery time was 24 days (range 12-65); operative mortality was 5.8% (7/121); general morbidity, including medical and surgical complications, was observed in 47 patients (38.8%). Pancreatic fistula occurred in 16 patients (13.2%); ten of these underwent a second operation. Patients who underwent pancreaticoduodenctomy were divided as follows: 76 pts. received a pylours-preserving pancreaticoduodenectomy and 45 a Whipple's resection. Neither surgical complications incidence nor mortality rate were significantly different between the two groups. Postoperative complications following pancreaticoduodenectomy are still frequent and severe. In particular, pancreatic fistula represents the most relevant complication following pancreaticoduodenectomy. The Authors suggest that standard and meticulous surgical procedures together with continued efforts to improve postoperative follow-up, support early detection of complications and improvement of results in most patients.

[Intraoperative cholangiography in videolaparoscopic cholecystectomy: indications, advantages, and limitations]

Consensus doesn't exist about the intraoperative cholangiography specially if is need in every one laparoscopic cholecystectomy either exclusively in case of anatomical doubts or suspect of injures or stones of the common duct. We have considered 450 patient subjected to laparoscopic cholecystectomy during 1992-2000. Patients suspicious to be affected by common duct lithiasis (28 cases) are subjected to ERCP with cleaning of the biliary tree. In 18 patients (4%) it has been necessary the laparotomic conversion; 176 patients (39%) have been subjected to intraoperative cholangiography, selected on anatomical regional disposition or anamnesis and biochemical and instrumental results (history of jaundice or gallstones pancreatitis, abnormal serum level of the biliary stasis biochemistry, common bile duct major of 8 mm, michrolitiasis of the gallbladder). In 7 cases (4%) we have discovered common bile duct stones. We don't attempt intraoperative cholangiography in every one laparoscopic cholecystectomy, but only in cases where we suspect presence of common bile duct stones either iatrogenic injuries or when we retain it necessary to clarify the regional anatomy. Unlikely just in patients where would be more useful, causes major risk of intra- and post-operative complications, it is very difficult, often impossible, to attempt the intraoperative cholangiography. Routinary employing of the intraoperative cholangiography could be useful just for a little number of patients, while selective employing reduce 60% the X-ray. Collaboration with the radiologist is able to reduce the mistaken on the interpretation of the radiograms.

Recombinant erythropoietin therapy as an alternative to blood transfusions in infants with hereditary spherocytosis

INTRODUCTION

In hereditary spherocytosis, erythropoiesis has been described as 'sluggish' during the first months of life. The lack of appropriate erythropoietic response to compensate for increased red cell destruction necessitates blood transfusions in 70-80% of hereditary spherocytosis-affected infants during their first year of life. After this period, less than 30% require regular transfusion support. This transient requirement for transfusion led us to wonder whether anemic hereditary spherocytosis infants, like anemic premature infants, could benefit from recombinant erythropoietin therapy (rHu-Epo).

MATERIAL AND METHODS

In 16 hereditary spherocytosis infants (age range 16-119 days) with severe anemia, a compassionate open preliminary study was performed. rHu-Epo treatment (1000 IU/kg/week) was instituted together with iron supplementation. Hemoglobin values and reticulocyte counts were repeatedly assessed.

RESULTS

In 13 out of 16 infants, prompt increases in reticulocyte counts were noted after the first week of treatment with 1000 IU/kg/week of rHu-Epo. During treatment with Epo these infants maintained clinically acceptable levels of hemoglobin and did not require blood transfusions. As the infants grew and began to mount an adequate erythropoietic response, the rHu-Epo dose could be tapered and the treatment could be discontinued before the age of nine months.

CONCLUSION

Epo treatment in most hereditary spherocytosis infants appears to be effective in the management of anemia and could serve as a valuable alternative to packed RBC transfusions.

[Non-invasive evaluation of the endothelial function using high-resolution B-mode ultrasonography]

The vascular endothelium has a central role in regulating vasomotor tone, smooth muscle cell proliferation, platelet and leukocyte adhesion to the arterial wall, thrombosis and fibrinolysis. Disturbances of these endothelial functions have been suggested to be important in the early and advanced phases of atherosclerosis. The development of a simple, valid ultrasound-based method allowed to non-invasively evaluate endothelial function in a large number of individuals with traditional and non-traditional cardiovascular risk factors. The ultrasound technique measures changes in brachial artery diameter in response to an increase in blood flow (reactive hyperemia) and thus in shear stress, which causes endothelium-dependent dilation. This methodology is not yet perfect. The critical issues today involve the definition of "normal values", and standardized scanning and reading protocols to reduce variability.

Natural history of congenital dyserythropoietic anemia type II

Congenital dyserythropoietic anemia type II (CDA-II) is an autosomal recessive disease characterized by anemia, jaundice, splenomegaly, and erythroblast multinuclearity. The natural history of the disease is unknown. The frequency, the relevance of complications, and the use of splenectomy are poorly defined. This study examined 98 patients from unrelated families enrolled in the International Registry of CDA-II. Retrospective data were obtained using an appropriate questionnaire. The mean age at presentation was 5.2 +/- 6.1 years. Anemia was present in 66% and jaundice in 53.4% of cases. The mean age at correct diagnosis was 15.9 +/- 11.8 years. Twenty-three percent of patients for whom data were available developed anemia during the neonatal period, and 10 of these individuals required transfusions. Splenectomy produced an increased hemoglobin (P <.001) and a reduced bilirubin level (P =.007) in comparison with values before splenectomy. Preliminary data indicate that iron overload occurs irrespective of the hemochromatosis genotype. (Blood. 2001;98:1258-1260)

[Septic complications of gallbladder lacerations during laparoscopic cholecystectomy]

The iatrogenic gallbladder perforation with bile and, eventually, gallstones loss in the peritoneal cavity happens in the laparoscopic cholecystectomies more frequently than in the laparotomic ones. The authors have reviewed their experience and recent bibliography with the aim to clarify factors that increase risks for this adverse effect; 579 patients subjected to laparoscopic cholecistectomy: in 81 cases (13.98%) the intra-peritoneal perforation of the gallbladder wall has happened, in 26 associated to gallstones loss; 12 of these last have developed abdominal wall infections. No case of intra-peritoneal abscess was observed. The Authors believe to be proper to select patients with the clinical and instrumental evaluation. They identify emergency and flogosis as risk factors for the perforations, as well the systemic illnesses for sepsis. They emphasize the role of antibiotic prophylaxis in the high risk subjects.

[Instability determinants of the carotid plaque: from histology to ultrasound]

Over the last decade, it has become progressively clear that the most important mechanism responsible for acute coronary and cerebrovascular events is atherosclerotic plaque rupture with superimposed thrombus formation. Anatomo-pathological studies have shown that the risk of rupture depends on plaque type rather than plaque size. The determinants of carotid plaque vulnerability to rupture are similar to those responsible for coronary instability: 1) size and consistency of the lipid-rich atheromatous core, 2) ongoing inflammation and repair processes within the fibrous cap, and 3) the thickness of the fibrous cap covering the core. Unstable plaques contain a soft, lipid-rich core that is covered by a thin and inflamed cap of fibrous tissue. External factors such as mechanical and hemodynamic stresses may be important not only in precipitating disruption of vulnerable plaques, but also in their cellular differentiation. Several imaging techniques have been used to identify plaques at high risk of events. High-resolution B-mode ultrasound is a noninvasive, inexpensive technique which allows a characterization of carotid plaque dimension, internal structure and surface. Nevertheless, such a method is not perfect. The subjective evaluation of plaque morphology on B-mode ultrasound, the need of improving reproducibility and the lack of a uniform terminology are critical issues, which need to be addressed.

[Role of the subfascial endoscopic perforator vein surgery in the treatment of venous ulcers]

BACKGROUND

Limbs phlebostatic ulcers are in many cases associated with perforator reflux veins often caused by post-thromboflebitis syndrome. The origin operation consisting in perforating vein interruption, described by Linton in 1938, allowed high quality exposition of these vessels and gave successful therapeutic results only affected by complications which prolonged hospitalisation. The most unfavorable prognostic factor was the need of performing an incision in skin sites affected by dermo-hypodermic degeneration induced by phlebopathy which inhibits post-surgery cicatrization. The therapeutic importance of reflux perforator vein interruption induced vascular surgeons to improve various procedures not affected by post-surgery complications and able to excise as much incontinent vessels as possible.

METHODS

By video-surgery and new surgery tools nowadays available, the Subfascial Endoscopic Perforating Veins Surgery (SEPS) was established as a feasible and valuable method. At present, there are many surgical techniques differing from each other for the tools and the subneurotic compartement from which the perforating veins start. The results obtained from 45 SEPS procedures performed on 45 patients presenting lymphodermatosclerosis or venous ulcers caused by chronic venous insufficiency have been retrospectively evaluated.

RESULTS

Thirty-six patients reached ulcer healing within 4 weeks after the operation; 7 ulcers healed over a 2 month time, while for 2 patients no clinical improvement has been recorded yet.

CONCLUSIONS

SEPS is a valid alternative to the Linton procedure and provides remarkable advantages both in economic and clinical terms since it yields a more rapid lesions healing of small incisions which makes it one of the most minimally invasive surgical technique.

Autosomal dominant macrothrombocytopenia in Italy is most frequently a type of heterozygous Bernard-Soulier syndrome

A form of autosomal dominant macrothrombocytopenia is characterized by mild or no clinical symptoms, normal platelet function, and normal megakaryocyte count. Because this condition has so far received little attention, patients are subject to misdiagnosis and inappropriate therapy. To identify the molecular basis of this disease, 12 Italian families were studied by linkage analysis and mutation screening. Flow cytometry evaluations of platelet membrane glycoproteins (GPs) were also performed. Linkage analysis in 2 large families localized the gene to chromosome 17p, in an interval containing an excellent candidate, the GPIbalpha gene. GPIbalpha, together with other proteins, constitutes the plasma von Willebrand factor (vWF) receptor, which is altered in Bernard-Soulier syndrome (BSS). In 6 of 12 families, a heterozygous Ala156Val missense substitution was identified. Platelet membrane GP studies were performed in 10 patients. Eight were distinguished by a reduction of GPs comparable to that found in a BSS heterozygous condition, whereas the other 2, without the Ala156Val mutation, had a normal content of platelet GPs. In conclusion, the current study provides evidence that most (10 of 12) patients with an original diagnosis of autosomal dominant macrothrombocytopenia shared clinical and molecular features with the heterozygous BSS phenotype. The remaining 2 affected subjects represented patients with "true" autosomal dominant macrothrombocytopenia; the GPIb/IX/V complex was normally distributed on the surface of their platelets. Thus, the diagnosis of heterozygous BSS must always be suspected in patients with inherited thrombocytopenia and platelet macrocytosis.

Reversible erythrocyte skeleton destabilization is modulated by beta-spectrin phosphorylation in childhood leukemia

The erythrocyte skeleton plays an essential role in determining the shape and deformability of the red cell. Disruption of the interaction between components of the red cell membrane skeleton may cause loss of structural and functional integrity of the membrane. Several observations based on studies in vitro strongly suggest that phosphorylation may modify interactions between proteins, leading to a reduced affinity. In particular, increased phosphorylation of beta-spectrin decreases membrane mechanical stability. In order to investigate the presence of membrane protein defects we investigated the erythrocyte membrane protein composition and phosphorylation in 22 children with leukemia at diagnosis and during the remission phase. Sixteen children had acute lymphoblastic leukemia (ALL), three had chronic myeloid leukemia (CML) and three had acute myeloid leukemia (AML). Ten patients (eight ALL and two CML) displayed elliptocytosis and poikilocytosis, an increase of spectrin dimers (41.8 +/- 15.6) and an enhanced phosphorylation of beta-spectrin (108 +/- 15%) at diagnosis. These alterations disappeared during the remission phase. This is the first demonstration of a reversible erythrocyte membrane alteration in leukemia. Since the beta-spectrin phosphate sites are located near the C-terminal region and close to the head of the beta-chain that is involved in dimer-dimer interaction, we supposed that the beta-chain phosphorylation has an effect upon the interactions between spectrin dimers, ie the tetramerization process. The weakening of this process should be responsible for the presence of elliptocytes and poikilocytes as reported in hereditary elliptocytosis and pyropoikilocytosis.

Flow-cytometric analysis of erythrocytes and reticulocytes in congenital dyserythropoietic anaemia type II (CDA II): value in differential diagnosis with hereditary spherocytosis

Congenital dyserythropoietic anaemia type II (CDA II) is the most common congenital dyserythropoietic anaemia. CDA II is frequently misdiagnosed as Hereditary Spherocytosis (HS) due to the presence of mild chronic haemolytic anaemia with splenomegaly, increased osmotic fragility, and presence of microspherocytes. Accurate diagnosis of CDA II is important to prevent severe iron overload. Erythrocyte and reticulocyte indices were assessed in 10 patients from six families with CDA II, 18 patients from eight families with HS, and 50 normal controls. Characteristic increases in distribution width were present in CDA II for cell volume (RDW, anisocytosis) and in HS for cell haemoglobin concentration (HDW, anisochromia), resulting in an RDW/HDW ratio which was significantly greater in CDA than HS (P < 0.0002). A cut-off value for RDW/HDW of 5.34 resulted in 89% sensitivity and 70% specificity in distinguishing CDA II from HS. Distribution width for cell haemoglobin content of reticulocytes (CHDWr) was characteristically increased in CDA II, resulting in a CHDW/CHDWr ratio significantly lower in CDA II than HS (P < 0.0002). A cut-off value of 0.98 provided 89% sensitivity and 80% specificity in distinguishing CDA II from HS. These differences in distribution widths of flow-cytometric parameters of reticulocytes and mature erythrocytes reflect the different pathogeneses of the two diseases and are helpful for the differential diagnosis of these two conditions.

Clinical and molecular evaluation of non-dominant hereditary spherocytosis

About 75% of hereditary spherocytosis (HS) patients have the autosomal dominant form of the disease, whereas both parents of the remaining HS patients are clinically and haematologically normal. These patients could have either the autosomal recessive form of the disease or a de novo mutation. We studied 80 randomly chosen, Italian HS children with normal parents. They had different clinical phenotypes (16 mild, 40 moderate, 16 moderately severe and eight severe). These patients were screened for the occurrence of ankyrin or beta-spectrin de novo mutations. To search for ankyrin de novo mutations affecting mRNA accumulation, we studied a (AC)(n) microsatellite located in the non-coding sequence of the last exon of the ankyrin gene, and four different exonic polymorphisms in the beta-spectrin gene were utilized for the detection of de novo mutations influencing beta-spectrin mRNA stability. They were also screened for the presence of alpha-spectrin(LEPRA) as well as for the mutation -108T-->C in the ankyrin promoter, two variants previously found in some cases of genuinely recessive HS. Twenty-five patients showed ankyrin de novo mutations and 10 HS subjects had beta-spectrin de novo mutations. Furthermore, we found five patients to be heterozygous for alpha-spectrin(LEPRA) and one heterozygous for the mutation in the ankyrin promoter. Therefore, a molecular diagnosis was achieved in about 50% of the cases. Our data demonstrate that, among HS patients with normal parents, de novo dominant mutants are six times more common than recessive mutations. These results should be considered in view of the genetic counselling of a normal couple with a HS child.

Osteoporosis in beta-thalassaemia major patients: analysis of the genetic background

Regular blood transfusions from infancy until adulthood in beta-thalassaemia major patients have substituted severe bone deformities with less marked skeletal lesions as osteoporosis. Osteoporosis is characterized by low bone mass and disruption of bone architecture, resulting in reduced bone strength and increased risk of fractures. Genetic factors have an important role in determining bone mineral density (BMD). We have investigated the possible association between BMD and two polymorphisms in 135 beta-thalassaemic patients: (i) a substitution G-->Tau in a regulatory region of the COLIA1 gene encoding for the major protein of bone (type 1 collagen), and (ii) a one-base deletion in intron 4 (713-8del C) of transforming growth factor beta 1 (TGF-beta1) gene. We have found a remarkable incidence (90%) of osteopenia and osteoporosis among regularly transfused patients. Bone mass was lower in men than in women (P = 0.0023), with a more prevalent osteopenia/osteoporosis of the spine in men than in women (P = 0. 001). The sample was stratified on the basis of BMD expressed as Z-score, i.e. normal, osteopenic and osteoporotic patients, and genotype frequencies of each group were evaluated. TGF-beta1 polymorphism failed to demonstrate a statistical difference in BMD groups. However, subjects with heterozygous or homozygous polymorphism of the COLIA1 gene showed a lower BMD than subjects without the sequence variation (P = 0.012). The differences among genotypes were still present when the BMD was analysed as adjusted Z-score and when men and women were analysed separately (P = 0.022 and 0.004 respectively), with men more severely affected. Analysis of COLIA1 polymorphism could help to identify those thalassaemic patients at risk of osteoporosis and fractures.

Geographic distribution of CDA-II: did a founder effect operate in Southern Italy?

BACKGROUND AND OBJECTIVE

Congenital dyserythropoietic anemia type II (CDA-II) is an autosomal recessive condition, whose manifestations range from mild to moderate. Its exact prevalence is unknown. Based on a recently established International Registry of CDA-II (64 unrelated kindreds), a high frequency of CDA II families living in South Italy became evident.

DESIGN AND METHODS

The aim of this study was to define the haplotypes of the CDA II kindreds living in Southern Italy based on markers D20S884, D20S863, RPN, D20S841 and D20S908. These markers map to 20q11.2, within the interval of the CDAN2 gene that is responsible for CDA II. Next, we looked at these markers in kindreds from other regions of Italy and from other countries, with special attention to families having ancestors in Southern Italy.

RESULTS

Evaluation of the geographic distribution of the ancestry of Italian CDA-II patients clearly demonstrated the unusually high incidence of this condition in Southern Italy. Our statistical calculations and linkage disequilibrium data also clearly demonstrate a strong association of the markers of chromosome 20 with the disease locus in our sample. Almost all the regions defined by the markers here used is in disequilibrium with the disease. Combining the data from the Italian sample together with those obtained from the non-Italian ones, we can restrict the area of highest disequilibrium to that defined by markers D20S863-D20S908.

INTERPRETATION AND CONCLUSIONS

Despite the presence of this linkage disequilibrium the search for a common haplotype failed. This could suggest that the mutation was very old or that it occurred more than once on different genetic backgrounds.

Gilbert's syndrome accounts for the phenotypic variability of congenital dyserythropoietic anemia type II (CDA-II)

The molecular basis for the considerable variation of serum bilirubin levels and the incidence of gallstone formation in patients with congenital dyserythropoietic anemia (CDA) type II are unknown. We show that the combined effect of an increased bilirubin load caused by dyserythropoiesis in CDA II and decreased bilirubin conjugation caused by reduced expression of uridine diphosphate glucuronosyl transferase (UGT1A) would increase the risk of hyperbilirubinemia (P <.005) and gallstone formation (chi(2): P <. 001). The rate of gallstone formation in patients with CDA II is 4. 75-fold the rate of patients without Gilbert's syndrome, and gallstone diagnosis occurs at a younger age (P < 0.01). These findings should be considered during the follow-up of patients with CDA II.

Heavy transfusions and presence of an anti-protein 4.2 antibody in 4. 2(-) hereditary spherocytosis (949delG)

BACKGROUND AND OBJECTIVE

A patient with hereditary spherocytosis (HS) was found not to have red cell membrane protein 4.2. This rare form of HS, or 4.2 (-) HS, stems from mutations within the ELB42 or the EPB3 genes. The patient had long suffered from a gastric ulcer and impaired liver function. He had had several dramatic episodes of gastrointestinal tract bleeding and had received numerous transfusions. An antibody against a high frequency, undefined antigen was found, creating a transfusional deadlock. We elucidated the responsible mutation and searched for an anti-protein 4.2 antibody.

DESIGN AND METHODS

Red cell membranes were analyzed by SDS-PAGE and by Western blotting. Nucleotide sequencing was performed after reverse transcriptase-polymerase chain reaction (RT-PCR) and nested PCR.

RESULTS

The not previously described mutation was a single base deletion: 949delG (CGCAECC, exon 7, codon 317) in the homozygous state. It was called protein 4.2 Nancy. The deletion placed a non-sense codon shortly downstream so that no viable polypeptide could be synthesized. The patient carried a strong antibody against protein 4.2 as shown by Western blotting.

INTERPRETATION AND CONCLUSIONS

The manifestations resulting from the mutation described were compared with the picture of HS stemming from other ELB42 gene mutations. We discuss the mechanism through which the anti-protein 4.2 antibody developed. There was no way to establish or to rule out whether the antibody participated in the transfusional deadlock found in our patient.

Familial dominant thrombocytopenia: clinical, biologic, and molecular studies

Inherited thrombocytopenias are a heterogenous group of disorders. Different criteria have been suggested to classify the forms, such as the inheritance mechanism and the platelet volume as well as the number and morphology of megakaryocytes. However, the classification is often descriptive, and the precise mechanism of thrombocytopenia still remains unknown. We describe the clinical, biologic, and molecular findings of an autosomal dominant thrombocytopenia in a large family. The 17 patients had normocellular bone marrow and normal platelet volume. Platelets also showed a normal aggregation test and normal response to ADP and thrombopoietin (TPO). In the affected subjects, the mean +/- SD levels of platelet count and plasma TPO were 62+/-25 and 258+/-151, respectively. Comparative analysis showed that the patients with platelet count <70000 had higher plasma TPO concentration. The data are consistent with a mild clinical form of the disease associated with only a few episodes of bleeding. To exclude the possible role of TPO and its receptor c-mpl in the etiology of this condition, linkage analysis was performed using microsatellite markers close to the TPO and c-mpl genes on chromosomes 3q26.3-q27 and 1p34, respectively. The absence of cosegregation within the affected family indicated that these genes, as well as two other candidate loci on chromosomes 11 and 21, are not responsible for this hereditary dominant form of thrombocytopenia. A genome-wide search and subsequent identification of the gene will provide new insight into the pathogenesis of this disorder.

An autosomal dominant thrombocytopenia gene maps to chromosomal region 10p

The increasing number of diagnosed cases of inherited thrombocytopenias, owing to the routine practice of including platelet counts in blood tests, suggests that this condition is not so rare as expected. In the majority of cases, the molecular basis of the disease is unknown, although the defect is likely to affect thrombocytopoiesis and regulation of the normal platelet count. Here we report a genomewide search in a large Italian family affected by autosomal dominant thrombocytopenia. Patients showed a moderate thrombocytopenia with minimal symptoms characterized by normocellular bone marrow, normal medium platelet volume, and positive aggregation tests. Microsatellite analysis demonstrated that the disease locus (THC2) is linked to chromosome 10p11.1-12, within a candidate region of 6 cM between markers D10S586 and D19S1639. A maximum LOD score of 8.12 at recombination fraction.00 was obtained with the microsatellite D10S588. These data localized the first locus of an autosomal dominant thrombocytopenia, and the subsequent identification of the gene will provide new insight into the basic mechanism of megakaryocytopoiesis disorders.

Coinheritance of Gilbert syndrome increases the risk for developing gallstones in patients with hereditary spherocytosis

The precocious formation of bilirubinate gallstones is the most common complication of hereditary spherocytosis (HS), and the prevention of this problem represents a major impetus for splenectomy in many patients with compensated hemolysis. Because Gilbert syndrome has been considered a risk factor for gallstone formation, there are reasons for postulating that the association of this common inherited disorder of hepatic bilirubin metabolism with HS could increase cholelithiasis. To test this hypothesis, 103 children with mild to moderate HS who, from age 1, have undergone a liver and biliary tree ultrasonography every year, were retrospectively examined. The 2-bp (TA) insertion within the promoter of the uridine diphosphate-glucuronosyltransferase gene (UGT1A1), associated with Gilbert syndrome, was screened. The risk of developing gallstones was statistically different among the 3 groups of patients: homozygotes for the normal UGT1A1 allele, heterozygotes, and homozygotes for the allele with the TA insertion. Fitting a Cox regression model, in fact, a statistically significant hazard ratio of 2.19 (95% confidence interval: 1.31 to 3.66) was estimated from one to the next of these genetic classes. The individual proneness to form gallstones from TA insertion in the TATA-box of the UGT1A1 promoter should be considered during the follow-up of patients with HS. Although patients with HS were the only ones studied, extrapolating these data to patients who have different forms of inherited (eg, thalassemia, intraerythrocytic enzymatic deficiency) or acquired (eg, autoimmune hemolytic anemia, hemolysis from mechanical heart valve replacement) chronic hemolysis can be warranted.