Sengers syndrome: six novel AGK mutations in seven new families and review of the phenotypic and mutational spectrum of 29 patients

Background

Sengers syndrome is an autosomal recessive condition characterized by congenital cataract, hypertrophic cardiomyopathy, skeletal myopathy and lactic acidosis. Mutations in the acylglycerol kinase (AGK) gene have been recently described as the cause of Sengers syndrome in nine families.

Methods

We investigated the clinical and molecular features of Sengers syndrome in seven new families; five families with the severe and two with the milder form.

Results

Sequence analysis of AGK revealed compound heterozygous or homozygous predicted loss-of-function mutations in all affected individuals. A total of eight different disease alleles were identified, of which six were novel, homozygous c.523_524delAT (p.Ile175Tyrfs*2), c.424-1G > A (splice site), c.409C > T (p.Arg137*) and c.877 + 3G > T (splice site), and compound heterozygous c.871C > T (p.Gln291*) and c.1035dup (p.Ile346Tyrfs*39). All patients displayed perinatal or early-onset cardiomyopathy and cataract, clinical features pathognomonic for Sengers syndrome. Other common findings included blood lactic acidosis and tachydyspnoea while nystagmus, eosinophilia and cervical meningocele were documented in only either one or two cases. Deficiency of the adenine nucleotide translocator was found in heart and skeletal muscle biopsies from two patients associated with respiratory chain complex I deficiency. In contrast to previous findings, mitochondrial DNA content was normal in both tissues.

Conclusion

We compare our findings to those in 21 previously reported AGK mutation-positive Sengers patients, confirming that Sengers syndrome is a clinically recognisable disorder of mitochondrial energy metabolism.

Video-assisted thoracoscopic patent ductus arteriosus closure in 2,000 patients

Video-assisted thoracoscopic surgery has proved to be a safe and effective method with low complication and high success rates. From 1997 to 2008, 2,000 consecutive patients with patent ductus arteriosus underwent closure of the ductus with 2 titanium clips via a video-assisted thoracoscopic technique. Complete closure was confirmed using our handmade intraesophageal stethoscope. The mean age was 5.2 years, and mean weight was 9.8 kg. One death was reported 1 month after surgery, due to sepsis during hospitalization for chylothorax treatment. The procedure was converted to an emergency thoracotomy in one case, due to ductal wall rupture. There were 4 late residual shunts treated via thoracotomy. We observed transient laryngeal nerve dysfunction in 14 patients. All patients were reassessed by postoperative echocardiography. The mean procedure (skin-to-skin) time was 10 ± 2 min, and hospitalization was 21 h. This study indicates that video-assisted thoracoscopic closure of patent ductus arteriosus is a safe, simple, and cost-effective method with low complication and high success rates. Furthermore, the cosmetic benefits make it appropriate as an out-patient procedure.

Congenital pulmonary arteriovenous malformation: a rare cause of cyanosis in childhood

Pulmonary arteriovenous malformation (PAVM) is a rare condition in which there is abnormal connection between pulmonary arteries and veins. The disorder usually appears in late childhood or early adult life, with dyspnea on exertion, clubbing or cyanosis. We present two patients with severe cyanosis and their work-up to diagnosis of PAVM, as a rare cause of cyanosis in childhood.