Clinical interest of molecular study in cases of isolated midline craniosynostosis.

In some cases of infants with apparently isolated single-suture synostosis, an underlying variant can be found. We aimed to determine the molecular substratum in isolated sagittal and metopic craniosynostosis. To this end, we included all infants who presented isolated midline synostosis (sagittal or metopic) and had undergone surgery at the craniosynostosis national reference center of Lyon University Hospital. All infants were examined by a multidisciplinary team including neurosurgeons, clinical geneticists and neuropsychologist. Among 101 infants tested, 13 carried a total of 13 variants; that is, 12.9% of the infants carried a variant in genes known to be involved in craniosynostosis. Seven infants carried SMAD6 variants, 2 in FGFR2, 1 in TWIST1, one in FREM1, one in ALX4 and one in TCF12. All variants were detected at the heterozygous level in genes associated with autosomal dominant craniosynostosis. Also, neurodevelopmental testing showed especially delayed acquisition of language in children with than without variants in SMAD6. In conclusion, a high percentage of young children with isolated midline craniosynostosis, especially in isolated trigonocephaly, carried SMAD6 variants. The interpretation of the pathogenicity of the genes must take into account incomplete penetrance, usually observed in craniosynostosis. Our results highlight the interest of molecular analysis in the context of isolated sagittal and/or metopic craniosynostosis to enhance an understanding of the pathophysiology of midline craniosynostosis.

Perception of dynamic action in patients with schizophrenia.

Neuropsychological studies have revealed that schizophrenic (SZ) patients have severe impairments in the cognitive integration of static and moving perceptual stimuli. Research on knowledge structures has shown that sequences of continuous actions are represented in memory as clusters of goal-directed events in a hierarchical manner. In the present study, we investigated the ability to segment familiar sequences of dynamic goal-directed actions into small and large meaningful units in a group of patients with schizophrenia (N = 16) and a group of healthy control subjects (N = 17). While viewing two videotaped movies, participants were requested to detect the transitions between component events at both low and high levels of the action categorical structure. Both groups detected significantly more events under the small-oriented condition as compared to the large-oriented condition. Differently from normal controls, patients recalled the event scenes in a detailed and fragmentary manner and showed considerable difficulties in detecting large action units. Moreover, low performance on action boundary detection significantly correlated with higher levels of disorganisation symptoms in patients with schizophrenia. A defective conceptual organisation of perceptive action knowledge would help to explain the severe everyday difficulties of these patients both in monitoring their own actions and in understanding others' intentions.

Selective attention to facial emotion and identity in schizophrenia.

The selective attention to facial emotion and identity was investigated in 12 patients with schizophrenia and 12 healthy participants. Both patients and controls were required to perform two classification tasks (according either to identity or emotion). Two separate values for identity (person A/person B) and for emotion (fear/anger) were used. When the classification task was on one dimension, the other dimension was either correlated, constant, or orthogonal (Garner WR. The Processing of Information and Structure. Potomac, MD: Erlbaum, 1974, Garner WR. Interaction of stimulus dimensions in concept and choice processes. Cognitive Psychology 1976;8:98-123). Results indicated that both patients and healthy participants had an asymmetrical pattern of performance: they were able to selectively attend to the identity of the face presented, regardless of the emotion expressed on the face, but variation in identity interfered with the classification of facial emotion. Moreover, a correlational study indicated that the identity interference on emotion classification for schizophrenic patients covaried with the severity of their negative symptoms. The selective attention competencies in schizophrenia and the independence hypothesis of emotion and face recognition are discussed in the framework of current face recognition models.