IVIC syndrome

Alternate names

Instituto Venezolano de Investigaciones Cientificas syndrome; Radial ray defects, hearing impairment, external ophthalmoplegia, and thrombocytopenia; Oculootoradial syndrome; OORS

Definition

IVIC syndrome is a very rare genetic malformation syndrome characterized by upper limb anomalies (radial ray defects, carpal bone fusion), extraocular motor disturbances, and congenital bilateral non-progressive mixed hearing loss.

Epidemiology

Prevalence of IVIC is not known. To date, four affected families from Venezuela, Italy, Hungary, and Turkey (discordant monozygotic twins) have been described.

Cause

• The syndrome has been linked to mutations in the SALL4 gene (20q13.2) encoding a transcription factor involved in the maintenance and self-renewal of embryonic and hematopoietic stem cells.
• Okihiro syndrome is a disorder allelic to IVIC syndrome.

Inheritance

Autosomal dominant pattern, a 50/50 chance.

• IVIC syndrome is inherited in an autosomal dominant manner.
• Genetic counseling should be offered to affected families, informing them of the 50% chance of offspring inheriting the disease-causing mutation and therefore being affected with the syndrome.

Signs and symptoms

• Asymmetrical upper limbs are a characteristic clinical manifestation.
• Thumb involvement is the most typical clinical manifestation and can range from absence or hypoplasia to the presence of a triphalangic thumb.
• Other upper limb anomalies include radial ray defects and carpal bone fusion.
• Upper limbs may be severely malformed.
• Extraocular motor disturbances and hearing loss of variable severity have also been reported.
• Some affected individuals have been reported to have mild thrombocytopenia, leukocytosis, shoulder girdle hypoplasia, cardiac involvement, kidney malrotation, intermediate anorectal malformation , or rectovaginal fistula.
• The clinical presentation is highly variable but lower limbs are normal.
• There have been reports of sudden death.

Diagnosis

The diagnosis is based on the clinical findings; defects in the carpal joint and fingers are found in the X-ray image .

NIH genetic and rare disease info

• NIH info on IVIC syndrome

IVIC syndrome is a rare disease.

IVIC syndrome Resources
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