Jason T. Su

Evidence for a Dystrophin Missense Mutation as a Cause of X-Linked Dilated Cardiomyopathy

BACKGROUNDnX-linked dilated cardiomyopathy (XLCM) has previously been shown to be due to mutations in the dystrophin gene, which is located at Xp21. Mutations in the 5 portion of the gene, including the muscle promoter, exon 1, and the exon 1-intron 1 splice site, have been reported previously. The purpose of this study was to analyze the originally described family with XLCM (and other) for dystrophin mutations.nnnMETHODS AND RESULTSnPolymerase chain reaction (PCR) was used to amplify genomic DNA, and reverse-transcriptase PCR amplified cDNA from RNA obtained from heart and lymphoblastoid cell lines. Primers to the muscle promoter, brain promoter, and Purkinje cell promoter were designed, in addition to the exon 1 to exon 14 regions of dystrophin. Single-strand conformation polymorphism analysis was used for mutation detection, and DNA sequencing defined the mutation. Protein modeling was used for amino acid and secondary structure analysis. A missense mutation in exon 9 at nucleotide 1043 was identified that causes an alanine to be substituted for threonine, a highly conserved amino acid, at position 279 (T279A). This mutation results in a change in polarity in the evolutionarily conserved first hinge region (H1) of the protein and substitution of a beta-sheet for alpha-helix in this portion of the protein, destabilizing the protein.nnnCONCLUSIONSnA novel missense mutation in exon 9 of dystrophin causing an abnormality at H1 leads to the cardiospecific phenotype of XLCM.

The Warden procedure for partially anomalous pulmonary venous connection to the superior caval vein

PURPOSEnWhen there is partially anomalous pulmonary venous connection to the superior caval vein, intracardiac repair alone can result in obstruction. Although the Warden procedure involving translocation of the superior caval vein is commonly performed as an alternative to atriocavoplasty, follow-up of a larger number of patients in the modern era is lacking. We report and discuss the experience of a single institution with the Warden procedure for correction of partially anomalous pulmonary venous connection to the superior caval vein.nnnMETHODSnSince 1995, all 16 patients presenting with partially anomalous pulmonary venous connection to the superior caval vein underwent the Warden procedure at a mean age of 7.1 +/- 4.2 years, with a range from 0.2 to 14.3 years, and a mean weight of 24.7 +/- 14.0 kg, with a range from 4.1 to 52.9 kg. There were 9 males and 7 females. In 8 patients, we performed 10 concomitant procedures, including closure of an atrial or ventricular septal defect in 7, and advancement of the aortic arch in the other.nnnRESULTSnThere were no deaths, and only one episode of postoperative sinus bradycardia with intermittent junctional rhythm, which resolved spontaneously during temporary atrial pacing. All patients were discharged home in normal sinus rhythm at an average of 4.1 +/- 2.2 days after the procedure, with a range from 2 to 10 days. All are currently in the first grade of the New York Heart Association up to 5.6 years postoperatively. There is currently no evidence of sinus nodal dysfunction, nor obstruction of the superior caval vein, in any patient.nnnCONCLUSIONnThe Warden procedure for partially anomalous pulmonary venous connection to the superior caval vein produces excellent results, preserves the function of the sinus node, and should be routinely considered for the repair of this lesion.

Detection of Active Coronary Arterial Vasculitis Using Magnetic Resonance Imaging in Kawasaki Disease

A 7-kilogram 3-month-old boy was hospitalized with a 5-day history of high fever (>103°F), macular rash, strawberry tongue, and persistent irritability. A diagnosis of Kawasaki disease was made and the patient received 2 doses of intravenous immunoglobulin, prednisone, and high-dose aspirin. His platelet count was significantly elevated to 1.4 million/μL.nnClinical examination revealed mild swelling of his fingertips and a diffuse macular rash. There was cervical and inguinal lymphadenopathy. The precordium was quiet and the first and second heart sounds were normal with no cardiac murmurs. The lungs were clear to auscultation and the abdominal examination was normal. A chest …