Fine mapping of a gene responsible for regulating dietary cholesterol absorption; founder effects underlie cases of phytosterolaemia in multiple communities

Sitosterolaemia (also known as phytosterolaemia, MIM 210250) is a rare recessive autosomal inherited disorder, characterised by the presence of tendon and tuberous xanthomas, accelerated atherosclerosis and premature coronary artery disease. The defective gene is hypothesised to play an important role in regulating dietary sterol absorption and biliary secretion, thus defining a molecular mechanism whereby this physiological process is carried out. The disease locus was localised previously to chromosome 2p21, in a 15 cM interval between microsatellite markers D2S1788 and D2S1352 (based upon 10 families, maximum lodscore 4.49). In this study, we have extended these studies to include 30 families assembled from around the world. A maximum multipoint lodscore of 11.49 was obtained for marker D2S2998. Homozygosity and haplotype sharing was identified in probands from non-consanguineous marriages from a number of families, strongly supporting the existence of a founder effect among various populations. Additionally, based upon both genealogies, as well as genotyping, two Amish/Mennonite families, that were previously thought not to be related, appear to indicate a founder effect in this population as well. Using both homozygosity mapping, as well as informative recombination events, the sitosterolaemia gene is located at a region defined by markers D2S2294 and Afm210xe9, a distance of less than 2 cM.     

Duchenne muscular dystrophy and myotonic dystrophy in the same patient

We report on the first patient identified with myotonic dystrophy and Duchenne muscular dystrophy (DMD). The family of the propositus had a strong history of myotonic dystrophy, and there was an intrafamilial pathological expansion of the responsible CTG repeat between the mildly affected mother (160 repeats; normal 27 repeats) and her more severely affected son (650 repeats), and his sister (650 repeats). The propositus was an isolated case of Duchenne muscular dystrophy with marked dystrophin deficiency in muscle biopsy. The patient was still ambulatory post age 16. Myotonic dystrophy could interfere to some extent with the progression of Duchenne dystrophy. However, other interpretations are possible. Twelve percent of dystrophin revertant fibers as observed by immunohistochemistry could be sufficient to ameliorate typical DMD clinical severity, or the patient may present a somatic mosaic. The pathophysiological interactions of these two unlinked disorders are discussed at the clinical and histopathological levels. © 1995 Wiley-Liss, Inc.     

Toll-like receptor 3 gene polymorphisms in South African Blacks with type 1 diabetes

Type 1 diabetes is the consequence of exposure of genetically susceptible individuals to specific environmental precipitants. The innate immune system provides the initial response to exogenous antigen and links with the adaptive immune system. The aim of this study was to assess the role of polymorphisms occurring in the cytoplasmic region of toll-like receptor (TLR) 3 gene and immediate 5' sequence, in subjects of Zulu descent with type 1 diabetes in KwaZulu-Natal, South Africa. Seventy-nine subjects with type 1 diabetes and 74 healthy normal glucose tolerant gender-matched control subjects were studied. Parts of exon 4 and exon 3/intron 3 of the TLR3 gene were studied by polymerase chain reaction, direct sequencing and restriction enzyme digestion with Bts 1. Of the nine polymorphisms studied, a significant association with type 1 diabetes was found for the major allele in the 2593 C/T polymorphism and for the minor alleles in the 2642 C/A and 2690 A/G polymorphisms, which were found to be in complete linkage disequilibrium. Correction of the P-values for the number of alleles studied, however, rendered the results no longer significant. These results suggest that polymorphisms in the TLR3 gene, which is part of the innate immune system, may be associated with type 1 diabetes in this population.     

Laparoscopic ICG-guided RALPPS procedure for HCC on cirrhosis with 3D reconstruction implementation: a case report

We present a fully laparoscopic partial RALPPS (radiofrequency-assisted liver partition with portal vein ligation for staged hepatectomy) on a cirrhotic 71-year...     

Low-intensity oral anticoagulant plus low-dose aspirin during the first six months versus standard-intensity oral anticoagulant therapy after mechanical heart valve replacement: a pilot study of low-intensity warfarin and aspirin in cardiac prostheses (LIWACAP).

The objective of this study was to evaluate the safety and efficacy of low-intensity warfarin treatment plus aspirin during the first 6 months after surgery in patients undergoing heart valve substitution with mechanical prostheses. Vitamin K antagonists (VKA) are able to reduce but not eliminate thrombosis and systemic embolism in patients with mechanical heart valves. The intensity of treatment and additional use of aspirin in these patients is still controversial. Consecutive patients undergoing aortic or mitral valve replacement (or a combination of the two) with mechanical prostheses were invited to participate in the study. After stratifying for site of prosthesis, patients were randomized to receive low intensity VKA treatment (target INR 2.5) plus aspirin (100 mg/day) for the first six months (Group A) or standard-intensity (INR target 3.7) VKA treatment (Group B). Mean follow-up was 1.5 years. Principal outcome events were systemic embolism, major bleeding, and vascular death. A total of 94 patients in Group A and 104 in Group B were randomized and followed up for 144 and 163 patient years, respectively. There were 5 (5%) events in Group A (4 major bleeding events and 1 vascular death) and 4 (4%) in group B (2 major bleeding events and 2 ischemic stroke). All the events except 1 occurred within the first 6 months after surgery. Cumulative incidence of primary outcome events was 5.8% (95% CI 0.9 to 10.7) in Group A and 4.3% (95% CI 0.2 to 8.4) in Group B (p=0.6). Low-intensity treatment plus aspirin during the first six months after surgery appears to be as effective and safe as moderate-high-intensity anticoagulation.     

Interleukin 2 does not promote the in vitro and in vivo proliferation and growth of human acute leukaemia cells of myeloid and lymphoid origin

The effect of recombinant interleukin 2 (IL2) on the in vitro and in vivo proliferation and growth of human acute leukaemia cells of both myeloid and lymphoid origin was investigated. In none of the 25 primary samples tested could a continuously in vitro growing cell line be obtained by adding IL2 to the culture medium. Although IL2 induced a proliferative signal in three of the 31 acute leukaemias analysed, the overall 3H-thymidine uptake of the neoplastic cells was significantly reduced (P less than 0.05) in the presence of IL2. The unlikelihood of an important proliferative signal triggered by IL2 was confirmed in a semisolid clonogenic assay, which failed to document an increased colony growth in the 26 samples studied. Furthermore, using a colorimetric assay as a test for cell proliferation and survival, in seven of the 11 fresh acute leukaemia samples tested a 22-40% reduction in viability was observed in the presence of IL2, while in the remaining four, IL2 was ineffective. In order to investigate the effect of IL2 in an in vivo setting, an experimental model in heavily immunosuppressed nu/nu mice was established. In no case did IL2 promote the in vivo proliferation and growth of human myeloid and lymphoid acute leukaemia cells injected in the mice. On the contrary, with seven of the eight leukaemic cell lines which gave rise spontaneously to leukaemic masses, this could be prevented when the mice received locally 300 U of IL2 three times daily for 90 d. IL2 also blocked the growth in vivo of three fresh acute leukaemia samples (two myeloid and one lymphoid). Co-culture experiments using leukaemic cell lines and increasing numbers of normal lymphocytes suggest that the inhibitory effect of IL2 is probably exerted via an indirect mechanism. These findings, coupled to the well-documented ability of IL2 to generate lymphokine activated killer cells cytolytic against leukaemic blasts, further point to the potential role of immunotherapy with IL2 in the management of patients with haematological malignancies.     

Genetic counseling of isolated carriers of Duchenne muscular dystrophy

It has recently become possible to detect female carriers of Duchenne muscular dystrophy with no affected male relative in the family. These “isolated carriers” represent about 10% of women with high serum creatine phosphokinase (CPK) levels and clinical evidence of a muscle disease. Most isolated carriers ascertained by clinical and/or CPK levels and diagnosed by dystrophin immunostaining of muscle biopsy show symptoms of a muscular dystrophy, and often carry the diagnosis of recessive “limb-girdle muscular dystrophy” prior to dystrophin analysis. It has been difficult to offer genetic counseling and prenatal diagnosis for Duchenne muscular dystrophy in the families of these isolated carriers, largely due to the difficulty in determining which of the dystrophin alleles segregating in the family harbors the mutation in the heterozygote. Here we report genetic counseling of three isolated carriers and their families. In two cases, prenatal diagnosis of at-risk pregnancies was conducted. We determined X inactivation patterns and inheritance of X chromosomes in each family, and used this information to define the at-risk dystrophin gene. In all three families, the mutation was a de novo event, two in the paternal germ-line, and one in the maternal germ-line. In each case we show that sibs of the heterozygous woman are at population risk, while pregnancies of each propositus are at high risk. Our results show that accurate genetic counseling and prenatal diagnosis can be offered to these families. © 1996 Wiley-Liss, Inc.     

Myoclonus in mitochondrial disorders

Myoclonus is a possible manifestation of mitochondrial disorders, and its presence is considered, in association with epilepsy and the ragged red fibers, pivotal for the syndromic diagnosis of MERRF (myoclonic epilepsy with ragged red fibers). However, its prevalence in mitochondrial diseases is not known. The aims of this study are the evaluation of the prevalence of myoclonus in a big cohort of mitochondrial patients and the clinical characterization of these subjects. Based on the database of the “Nation‐wide Italian Collaborative Network of Mitochondrial Diseases,” we reviewed the clinical and molecular data of mitochondrial patients with myoclonus among their clinical features. Myoclonus is a rather uncommon clinical feature of mitochondrial diseases (3.6% of 1,086 patients registered in our database). It is not strictly linked to a specific genotype or phenotype, and only 1 of 3 patients with MERRF harbors the 8344A>G mutation (frequently labeled as “the MERRF mutation”). Finally, myoclonus is not inextricably linked to epilepsy in MERRF patients, but more to cerebellar ataxia. In a myoclonic patient, evidences of mitochondrial dysfunction must be investigated, even though myoclonus is not a common sign of mitochondriopathy. Clinical, histological, and biochemical data may predict the finding of a mitochondrial or nuclear DNA mutation. Finally, this study reinforces the notion that myoclonus is not inextricably linked to epilepsy in MERRF patients, and therefore the term “myoclonic epilepsy” seems inadequate and potentially misleading. © 2014 International Parkinson and Movement Disorder Society