Learning Objectives
- Identify the genetic defect associated with Cri-du-chat syndrome.
- Recognize the pathognomonic clinical features, specifically the characteristic cry.
- Understand the associated cardiac complications.
1. Genetics
Cri-du-chat syndrome (French for “cry of the cat”) is a rare genetic disorder caused by a structural chromosomal abnormality.
- Defect: Congenital deletion of the short arm (p arm) of chromosome 5.
- Karyotype: 46, XX, 5p− or 46, XY, 5p−.
2. Clinical Manifestations
The presentation is dominated by neurodevelopmental delays and distinct physical characteristics.
| Feature | Clinical Findings |
|---|---|
| The “Cat” Cry | High-pitched crying/mewing; due to abnormal laryngeal development (usually resolves with age). |
| Neurological | Microcephaly and moderate to severe intellectual disability. |
| Facial | Epicanthal folds, hypertelorism (wide-set eyes), and a round face. |
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3. Cardiac Association & Mnemonic
The most common cardiac defect associated with Cri-du-chat is a Ventricular Septal Defect (VSD).
High-Yield Mnemonic: “I cry when I am Very SaD” (Ventricular Septal Defect).
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