Hereditary polymalformative syndrome characterized by
hearing impairment, radial ray defects and hand anomalies, internal
ophthalmoplegia, thrombocytopenia, and leukocytosis.
Arias Syndrome; Oculo-Oto-Radial Syndrome (OO-RS).
IVIC is an acronym that stands for Instituto Venezolano de
Investiaciones Cientifícas, where Sergio Arias Cazorla, a Venezuela
This syndrome was observed in 19 living descendants of a
Caucasoid family that migrated to Venezuela from the Canary Islands in the
Autosomal dominant with complete penetrance
and widely variable expression. Investigation on monozygotic twins indicated
that modification of OORS gene expression must be environmental or
epigenetic rather than genetic. It may represent an “iceberg dominant”
trait because of the wide range of severity.
The gene responsible for this syndrome has
variable expressivity, with the most consistent manifestation being a
developmental defect of the upper limbs. A mesenchymally based defect could
be implicated in the pathogenesis.
The radial ray is consistently
involved, with degrees of severity ranging from an almost normal thumb to a
hypoplastic, triphalangeal thumb attached to the radial border of the second
digit. Long and slender metacarpal bones and hypoplastic carpal bones may
coexist with proximally fused ulna and radius. One patient had a single
forearm bone. Other findings include hearing loss (very frequent),
extraocular muscle involvement in the form of strabismus (frequent), mild
thrombocytopenia and leukocytosis (less frequent), and imperforated anus
(10% of patients). Although very rare, incomplete right bundle branch
block has been reported in both children and adults. Clinical examination,
upper limb radiographs, audiograms, ophthalmologic examination, and blood
cell count contribute to the diagnosis.
Obtain blood cell count: possibility
of mild thrombocytopenia and/or leukocytosis. Obtain an electrocardiogram (ECG): rare reported
cases of incomplete right bundle branch block with occasionally increased QT
interval were not associated with any significant cardiovascular
If present, thrombocytopenia is mild and
usually does not necessitate platelet transfusion. Nonetheless, if
locoregional anesthesia is considered, an adequate platelet level should be
obtained before proceeding. The rare cardiac manifestations in the form of
ECG changes mentioned under Precautions Before Anesthesia have been described as “benign and single
cardiac sign” by the authorities on OORS.
No known implications with this
Holt-Oram Syndrome: Autosomal dominant polymalformative syndrome
caused by defective development embryonic development of the radial ray
associated with cardiac malformation (atrial septal defect). Mapped to band
12q24.1 (gene encoding the human transcription factor TBX5).
TAR Syndrome (Thrombocytopenia and Absent Radius):
Autosomal recessive syndrome characterized by
thrombocytopenia with potentially severe bleeding episodes, primarily during
infancy, aplasia of the radius (the ulna is often involved, too), and
various malformations (heart, kidneys).
Arias S, Penchaszadeh VB, Pinto-Cisternas J, et al: The IVIC syndrome: A
new autosomal dominant complex pleiotropic syndrome with radial ray
hypoplasia, hearing impairment, external ophthalmoplegia, and
thrombocytopenia. Am ...