[Fracture of the carpal scaphoid in children. Case report and literature review]

OBJECTIVE

To conduct a bibliographic review of the infrequent fractures of the carpal scaphoid in pediatric cases based on a clinical case. The diagnosis is usually a difficult one and treatment should be stringent in order to minimize the chance of delayed healing or pseudoarthrosis.

MATERIAL AND METHODS

Ten year-old child with a carpal scaphoid fracture visible in the plain films. The patient did not comply with treatment and removed the cast at three weeks. Despite this healing occurred without any clinical sequelae.

DISCUSSION

This case is especially infrequent given the excellent result obtained despite the fact that the immobilization period was considerably shorter than the minimum recommended.

Loss-of-function mutations in the cardiac calcium channel underlie a new clinical entity characterized by ST-segment elevation, short QT intervals, and sudden cardiac death

BACKGROUND

Cardiac ion channelopathies are responsible for an ever-increasing number and diversity of familial cardiac arrhythmia syndromes. We describe a new clinical entity that consists of an ST-segment elevation in the right precordial ECG leads, a shorter-than-normal QT interval, and a history of sudden cardiac death.

METHODS AND RESULTS

Eighty-two consecutive probands with Brugada syndrome were screened for ion channel gene mutations with direct sequencing. Site-directed mutagenesis was performed, and CHO-K1 cells were cotransfected with cDNAs encoding wild-type or mutant CACNB2b (Ca(v beta2b)), CACNA2D1 (Ca(v alpha2delta1)), and CACNA1C tagged with enhanced yellow fluorescent protein (Ca(v)1.2). Whole-cell patch-clamp studies were performed after 48 to 72 hours. Three probands displaying ST-segment elevation and corrected QT intervals < or = 360 ms had mutations in genes encoding the cardiac L-type calcium channel. Corrected QT ranged from 330 to 370 ms among probands and clinically affected family members. Rate adaptation of QT interval was reduced. Quinidine normalized the QT interval and prevented stimulation-induced ventricular tachycardia. Genetic and heterologous expression studies revealed loss-of-function missense mutations in CACNA1C (A39V and G490R) and CACNB2 (S481L) encoding the alpha1- and beta2b-subunits of the L-type calcium channel. Confocal microscopy revealed a defect in trafficking of A39V Ca(v)1.2 channels but normal trafficking of channels containing G490R Ca(v)1.2 or S481L Ca(v beta2b)-subunits.

CONCLUSIONS

This is the first report of loss-of-function mutations in genes encoding the cardiac L-type calcium channel to be associated with a familial sudden cardiac death syndrome in which a Brugada syndrome phenotype is combined with shorter-than-normal QT intervals.