Timothy Syndrome is an uncommon disorder with prominent cardiac arrhythmias.


Chromosome: 12p13.33

Locus: LQT8

Gene affected: CACNA1C affecting the Cav1.2 calcium channel.

Protein: voltage-dependent L-type calcium channel subunit alpha-1C


Cases often arise de novo.


Cardiac findings:

(1) QTc > 480 milliseconds

(2) functional 2:1 AV block

(3) bradycardia

(4) tachyarrhythmia

(5) congenital heart defect (patient ductus arteriosus, others)

(6) cardiomyopathy


Findings involving hands and feet:

(1) syndactyly of toes 2 and 3

(2) syndactyly of fingers

(3) joint contractures


Facial findings:

(1) depressed nasal bridge

(2) low-set ears

(3) thin vermilion border of the upper lip

(4) rounded face

(5) baldness at birth and during infancy

(6) small, widely spaced teeth


Neuropsychiatric findings may include:

(1) global developmental delays

(2) autism spectrum disorder

(3) seizures

(4) intellectual disability

(5) hypotonia


Complications may include:

(1) severe hypoglycemia

(2) frequent infections associated with abnormal immune response


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