New IEM: Mitochondrial Phosphate-Carrier Deficiency

• January 12th, 2007

Mitochondrial Phosphate-Carrier Deficiency: A Novel Disorder of Oxidative Phosphorylation
Johannes A. Mayr, Olaf Merkel, Sepp D. Kohlwein, Boris R. Gebhardt, Hansjosef Böhles, Ulrike Fötschl, Johannes Koch, Michaela Jaksch, Hanns Lochmüller, Rita Horváth, Peter Freisinger, and Wolfgang Sperl
The American Journal of Human Genetics, volume 80 (2007)

 
This group describes two patients from the same family, who presented with hypotonia and cardiomyopathy. Investigations revealed defective ATP synthesis in muscle. After excluding potentially culptrit genes, they sequenced SLC25A3, and identified and then proved a deficiency in the mitochodrial phosphate carrier. And thus a new inborn error of metabolism is described.

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Philippe Campeau, MD
Resident in Medical Genetics at McGill University
OMMBID Blog Administrator

Congenital myasthenic syndromes

• October 26th, 2006

Science. 2006 Sep 29;313(5795):1975-8.

Dok-7 mutations underlie a neuromuscular junction synaptopathy.

Beeson D, Higuchi O, Palace J, Cossins J, Spearman H, Maxwell S, Newsom-Davis J, Burke G, Fawcett P, Motomura M, Muller JS, Lochmuller H, Slater C, Vincent A, Yamanashi Y.

A new gene involved in a congenital myasthenic syndrome, in this case with proximal muscle weakness, has been identified. It was found earlier this year that dok-7 knock-out mice could not form acetylcholine receptor clusters nor neuromuscular synapses.

Science 23 June 2006 312: 1802-1805

The Muscle Protein Dok-7 Is Essential for Neuromuscular Synaptogenesis

Kumiko Okada, Akane Inoue, Momoko Okada, Yoji Murata, Shigeru Kakuta, Takafumi Jigami, Sachiko Kubo, Hirokazu Shiraishi, Katsumi Eguchi, Masakatsu Motomura, Tetsu Akiyama, Yoichiro Iwakura, Osamu Higuchi, and Yuji Yamanashi
 

The next step was to screen patients with congenital mysthenic syndromes for mutations in the gene encoding dok-7.
For a review of congenital mysthenic syndromes, see this article by Andrew Engel:

Curr Opin Pharmacol. 2005 Jun;5(3):308-21.

Current understanding of congenital myasthenic syndromes.

Engel AG, Sine SM
 

For a review of channelopathies, please see chapter 204 of OMMBID.

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Philippe Campeau, MD
Resident in Medical Genetics at McGill University
OMMBID Blog Administrator