Cardiac arrest refractory to standard intervention in atypical Timothy syndrome (LQT8 type 2).
نویسندگان
چکیده
Timothy syndrome (TS) is a rare, multisystem disorder most commonly associated with profound QTc prolongation and cutaneous dysmorphia arising from mutations of the L-type calcium channel. We present a case of a 12-day-old newborn who presented with respiratory distress and cyanosis. Diagnostic workup was notable for multiple cardiac abnormalities, and genetic analysis was consistent with an exon 8 mutation of the CACNA1C gene, which is diagnostic for TS type 2 (atypical TS). This patient presented with a novel constellation of symptoms, without dysmorphic features, and with a more moderate QTc interval. The heterogeneity of phenotypes suggests that this disorder may be characterized by variable expressivity or a spectrum of disease rather than a clearly defined syndrome.
منابع مشابه
Restoration of normal L-type Ca2+ channel function during Timothy syndrome by ablation of an anchoring protein.
RATIONALE L-type Ca(2+) (Ca(V)1.2) channels shape the cardiac action potential waveform and are essential for excitation-contraction coupling in heart. A gain-of-function G406R mutation in a cytoplasmic loop of Ca(V)1.2 channels causes long QT syndrome 8 (LQT8), a disease also known as Timothy syndrome. However, the mechanisms by which this mutation enhances Ca(V)1.2-LQT8 currents and generates...
متن کاملClinical characteristics and genetic background of congenital long-QT syndrome diagnosed in fetal, neonatal, and infantile life: a nationwide questionnaire survey in Japan.
BACKGROUND Data on the clinical presentation and genotype-phenotype correlation of patients with congenital long-QT syndrome (LQTS) diagnosed at perinatal through infantile period are limited. A nationwide survey was conducted to characterize how LQTS detected during those periods is different from that in childhood or adolescence. METHODS AND RESULTS Using questionnaires, 58 cases were regis...
متن کاملBrief UltraRapid Communication Restoration of Normal L-Type Ca Channel Function During Timothy Syndrome by Ablation of an Anchoring Protein
Rationale: L-type Ca (CaV1.2) channels shape the cardiac action potential waveform and are essential for excitation–contraction coupling in heart. A gain-of-function G406R mutation in a cytoplasmic loop of CaV1.2 channels causes long QT syndrome 8 (LQT8), a disease also known as Timothy syndrome. However, the mechanisms by which this mutation enhances CaV1.2-LQT8 currents and generates lethal a...
متن کاملLong QT syndrome type 8: novel CACNA1C mutations causing QT prolongation and variant phenotypes.
AIMS CACNA1C mutations have been reported to cause LQTS type 8 (LQT8; Timothy syndrome), which exhibits severe phenotypes, although the frequency of patients with LQT8 exhibiting only QT prolongation is unknown. This study aimed to elucidate the frequency of CACNA1C mutations in patients with long QT syndrome (LQTS), except those with Timothy syndrome and investigate phenotypic variants. METH...
متن کاملIncreased coupled gating of L-type Ca2+ channels during hypertension and Timothy syndrome.
RATIONALE L-Type (Cav1.2) Ca(2+) channels are critical regulators of muscle and neural function. Although Cav1.2 channel activity varies regionally, little is known about the mechanisms underlying this heterogeneity. OBJECTIVE To test the hypothesis that Cav1.2 channels can gate coordinately. METHODS AND RESULTS We used optical and electrophysiological approaches to record Cav1.2 channel ac...
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عنوان ژورنال:
- Proceedings
دوره 29 2 شماره
صفحات -
تاریخ انتشار 2016