Schmid-Fraccaro syndrome

Schmid-Fraccaro Syndrome Schmid-Fraccaro syndrome, also known as Cat Eye Syndrome (CES), is a rare chromosomal disorder characterized by a partial trisomy or tetrasomy of chromosome 22. This condition is named after the distinctive ocular coloboma that resembles a cat's eye, although not all individuals with the syndrome exhibit this feature.

Etiology

Schmid-Fraccaro syndrome is caused by the presence of an extra chromosome 22, specifically an inverted duplication of the short arm and a portion of the long arm of chromosome 22. This chromosomal anomaly is often referred to as a supernumerary marker chromosome, or an idic(22) chromosome.

Clinical Features

The clinical presentation of Schmid-Fraccaro syndrome is highly variable, but common features include:

• Ocular Coloboma: A key feature in some patients, leading to the "cat eye" appearance.
• Anal Atresia: A congenital defect where the anal opening is absent or misplaced.
• Ear Anomalies: Including preauricular tags or pits.
• Congenital Heart Defects: Such as total anomalous pulmonary venous return (TAPVR).
• Renal Malformations: Including kidney dysplasia or agenesis.
• Developmental Delays: Varying degrees of intellectual disability and developmental delays.

Diagnosis

Diagnosis of Schmid-Fraccaro syndrome is typically confirmed through cytogenetic analysis, which reveals the presence of the extra chromosome 22. Fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (aCGH) are commonly used techniques.

Management

Management of Schmid-Fraccaro syndrome is symptomatic and supportive, often requiring a multidisciplinary approach. Treatment may involve:

• Surgical Interventions: To correct anal atresia, heart defects, or other structural anomalies.
• Developmental Support: Including physical, occupational, and speech therapy.
• Regular Monitoring: For potential complications such as renal issues or hearing loss.

Prognosis

The prognosis for individuals with Schmid-Fraccaro syndrome varies widely depending on the severity of symptoms and associated anomalies. Early intervention and supportive care can improve quality of life and developmental outcomes.

Epidemiology

Schmid-Fraccaro syndrome is considered a rare disorder, with an estimated prevalence of 1 in 50,000 to 1 in 150,000 live births. The condition affects both males and females equally.

See Also

• Chromosomal Disorders
• Congenital Anomalies
• Genetic Counseling

External Links

• Genetic and Rare Diseases Information Center (GARD)
• National Organization for Rare Disorders (NORD)

NIH genetic and rare disease info

• NIH info on Schmid-Fraccaro syndrome

Schmid-Fraccaro syndrome is a rare disease.