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Our results support that SCN1B is the gene responsible in one amongst the six FS Tunisian families studied and might contribute to the FS susceptibility for the five others.

The mutation analysis and statistical test of the GABRG2 gene revealed a disease association with rs211014 in intron 8 (chi(2) = 5.25, P = 0.021). A sequencing analysis of the SCN1A gene was performed for the two tested families and showed a known mutation (c.1811G>A) and a putative disease-associated haplotype in only one family. Our results support that SCN1A is the responsible gene for GEFS+ in one of the two studied Tunisian families and suggest a positive association of an intronic SNP in the GABRG2 gene in both families.

Mitochondrial DNA defects were known to be associated with a wide spectrum of human diseases and patients might present a wide range of clinical features in various combinations. In the current study, we described a patient with psychomotor and neurodevelopmental delay, mild hyperintensity of posterior periventicular white matter, generalized clonic seizures, leukodystrophy, and congenital deafness. He also had tetraplegia, with central blindness and swallowing difficulty. Brain magnetic resonance imaging (MRI) showed involvement of the interpeduncular nucleus and central tegmental tract, white matter abnormalities, and cerebellar atrophy. A whole mitochondrial genome screening revealed the presence of 19 reported polymorphisms and an undescribed A to G mutation at nucleotide 8411 (p.M16V) affecting a conserved region of the mitochondrial adenosine triphosphatase (ATPase) 8 protein. This de novo mutation was detected in heteroplasmic form (97%) and was absent in 120 controls. Thus, the m.8411A>G mutation could strongly be associated with the disease in the tested patient.

Club foot is a common congenital deformity, for which a neurogenic process in utero has been proposed in some severe forms, but in most cases its cause remain uncertain. We report on four patients with an unilateral (three cases) or bilateral (one case) clubfoot and a bilateral perisylvian cortical dysplasia. All had severe dysarthria with mild mental retardation, epilepsy occurred in three cases. Direct evidence of fetal lesions of the spinal cord was occasionally present, such as signs of motor axonopathy in two cases analyzed by electrophysiological methods and syringomyelic cavitation at the thoracic level in one case. Even though the sensitivity of the investigations to demonstrate microcopic scars in the spinal cord remains weak, the presence of polymicrogyric rearrangements in the perisylvian cortex, known to proceed from a transient ischemic process occurring in the carotid territory during mid-gestation, strongly suggests that a similar mechanism occurred in the spinal cord. In fact, the foot deformity cannot be viewed as the consequence of lesions to brain regions that do not control the foot motility in the fetus. Extraneurological lesions such as jejunal atresia, possibly proceeding from localized vascular compromise, were also encountered. In one sibship, one sister was found to have a severe developmental anomaly of one foot, suggesting that genetic factors may be involved.

Cytochrome c oxidase is an essential component of the mitochondrial respiratory chain that catalyzes the reduction of molecular oxygen by reduced cytochrome c. In this study, the authors report the second mutation associated with Leigh syndrome in the blood and buccal mucosa of 2 affected members of a Tunisian family. It was a novel heteroplasmic missense mitochondrial mutation at nucleotide 9478 in the gene specifying subunit III of cytochrome c oxidase substituting the valine at position 91 to alanine in a highly conserved amino acid. It was found with a high mutant load in tissues derived from endoderm (buccal mucosa) and mesoderm (blood). However, it was nearly absent in tissue derived from ectoderm (hair follicles). It was absent in 120 healthy controls, and PolyPhen analysis showed that the hydropathy index changed from +1.276 to +0.242, and the number of structures of the 3D protein decreased from 39 to 32.

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