Clinical genetics
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Case Reports
Vascular ring leading to tracheoesophageal compression in a patient with Rubinstein-Taybi syndrome.
Mediastinal vascular rings cause tracheoesophageal obstruction, resulting in respiratory symptoms and dysphagia in children. Although a large number of children with Rubinstein-Taybi syndrome have frequent respiratory infections and feeding difficulties, there has been no firmly established association between this syndrome and the occurrence of vascular rings. We report on a patient with Rubinstein-Taybi syndrome who had a vascular ring. Since there was a previous report of a similar ring in a child with Rubinstein-Taybi syndrome, we suggest there may be an association between Rubinstein-Taybi syndrome and vascular rings.
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Eight mutations in the gene (the RYR1 gene) encoding the calcium release channel of sarcoplasmic reticulum (SR) in skeletal muscle are so far known to be very closely linked to malignant hyperthermia susceptibility in man and are regarded to be causative. We have examined 41 Swedish families where malignant hyperthermia had occurred in at least one member during anaesthesia, with respect to three of the known mutations. ⋯ In three (i.e. 7%) of the families we detected the Arg614Cys mutation, and this was the only one of the mutations searched for that was observed. This indicates that other mutations than those searched for in this study must cause malignant hyperthermia susceptibility in most Swedish malignant hyperthermia susceptible families.
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Association studies were carried out in a sample of 86 patients from Sweden who had survived a myocardial infarction (MI) at a young age and 93 age-matched healthy individuals, to compare the impact of polymorphisms at the apolipoprotein (apo) AI-CIII-AIV gene cluster on among-individual differences in plasma lipid and lipoprotein traits, the five high density lipoprotein (HDL) subclasses (2b to 3c), lipoprotein lipase (LPL) activity and presence and progression of atherosclerosis. Individuals were genotyped for four polymorphisms; 5'apoAI (G/A-75), 3'apoAI (PstI; P +/-), apoCIII (C/T1100) and apoCIII (PvuII; V +/-), using PCR-based techniques. Allele frequencies were similar in healthy individuals and patients (frequencies of alleles in combined population: 5'apoAI-A-75 = 0.14, 3'apoAI-P- = 0.05, apoCIII-T1100 = 0.27 and apoCIII-V- = 0.18). ⋯ In the patient group only, levels of protein in HDL2b, HDL2a and HDL3b subclasses were significantly associated with genotypes of the LPL-HindIII polymorphism (22.1, 19.3 and 11.4%, respectively, of sample variance; p < 0.05). Finally, associations were examined between genotypes at the apoAI-CIII-AIV gene cluster and the extent of coronary atherosclerosis. Global severity of atherosclerosis at the first angiography was weakly associated with genotypes of the apoCIII-C/T1100 polymorphism, presence of the T1100 allele being associated with 53% lower median score (1.6 vs 0.75; p = 0.09).(ABSTRACT TRUNCATED AT 400 WORDS)
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Case Reports
X-linked recessive nephritis with mental retardation, sensorineural hearing loss, and macrocephaly.
A family with hereditary nephritis, sensorineural hearing loss, macrocephaly, and mental retardation is reported. X-linked recessive inheritance was suggested by the presence of two affected brothers and a maternal uncle. This association may be a previously unreported variant of Alport's syndrome.
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Case Reports
Wolman disease: morphological, clinical and genetic studies on the first Scandinavian cases.
On the Aland Islands, a 1-month-old girl was diagnosed as having Wolman disease. The diagnosis was confirmed neurochemically; a decreased activity of acid lipase was noted in the proband and her parents had typical carrier values. This is the first Scandinavian case reported. ⋯ Genealogical analyses revealed that the index families had ancestors from the same restricted area and also common ancestors during the 17th century. The parents of the two affected sibs were born on a small island and were related in many different ways. On the basis of genealogical studies and other genetic investigations performed, the importance of founder and drift effect for manifestations of rare hereditary disorder in isolates is stressed.