A concise clinical reference for physicians, genetic counselors, nurses, therapists, and first responders encountering 5p- Syndrome — including diagnostic guidance, clinical characteristics, downloadable fact sheets, and referral pathways.
5p- Syndrome (Cri du Chat Syndrome; OMIM 123450) results from a partial deletion of the short arm of chromosome 5. It is among the more common chromosomal deletion syndromes, with an estimated incidence of 1 in 15,000–50,000 live births.
The deletion occurs on the short arm of chromosome 5 (5p). The critical region for the characteristic high-pitched cry maps to 5p15.3, while the region associated with intellectual disability maps primarily to 5p15.2. Deletion size correlates broadly with phenotypic severity — larger deletions are associated with more significant intellectual disability.
Approximately 85% of cases represent de novo deletions. In 10–15% of cases, one parent carries a balanced chromosomal rearrangement (typically a translocation), which significantly increases recurrence risk and warrants family counseling.
Prevalence estimates are derived from published case series and registry data. Individual presentation varies significantly based on deletion size.
| System | Finding | Frequency | Clinical notes |
|---|---|---|---|
| General / Neonatal | High-pitched, cat-like cry (Cri du Chat) | ~95% | Pathognomonic in neonates; due to laryngeal and neurological abnormalities; typically resolves by age 2 |
| Low birth weight / FTT | >75% | Hypotonia and poor suck contribute to feeding difficulties and failure to thrive in infancy | |
| Microcephaly | 50–70% | Usually mild; progressive in some | |
| Craniofacial | Hypertelorism | >80% | Wide-set eyes; often with epicanthal folds |
| Low-set ears | >70% | May contribute to recurrent otitis media | |
| Micrognathia | ~50% | Can affect feeding and airway in newborn period | |
| Neurological | Intellectual disability | >90% | Ranges from mild to profound; correlates with deletion size; significant therapy-responsiveness |
| Hypotonia | ~95% | Universal in infancy; improves with age and PT intervention; scoliosis risk secondary | |
| Behavioral | Hyperactivity / ADHD-like | ~50–70% | Often improves with structured environment; stimulant medications used cautiously |
| Stereotypies / self-stimulation | ~40–60% | Self-injurious behavior occurs in a subset; behavioral interventions primary | |
| Cardiac | Congenital heart defects | ~30% | ASD and VSD most common; echocardiogram recommended at diagnosis |
| Patent ductus arteriosus | ~15% | ||
| Musculoskeletal | Scoliosis | ~15–30% | Secondary to hypotonia; monitor with annual spinal exam; may require bracing or surgery |
| Hip dysplasia | ~15% | Screen with hip radiographs in hypotonic infants | |
| Ophthalmologic | Strabismus | >60% | Early ophthalmology referral recommended |
| Audiologic | Sensorineural or mixed hearing loss | ~15–30% | Formal audiology evaluation at diagnosis; recurrent OM may contribute to conductive component |
Preferred diagnostic test. Characterizes deletion size and breakpoints. Also detects unexpected copy number variants that may modify the phenotype. Required for recurrence risk counseling.
Targeted FISH using 5p15.3 probe confirms the deletion rapidly. Used in neonatal/urgent settings or to confirm CMA findings. Does not characterize full deletion extent.
Conventional karyotype for both parents. Detects balanced translocations or inversions that may carry a recurrence risk of 10–25%. Critical for family counseling and future pregnancy planning.
Detectable on routine chromosomal microarray from CVS or amniocentesis. May be identified incidentally on NIPS/NIPT (cell-free DNA) — though NIPT sensitivity for this deletion varies by platform.
Printable and shareable documents for clinical practice, genetic counseling, and referral.
Two-page clinical summary for the generalist physician. Covers genetics, features, workup, and referral recommendations.
DownloadRecurrence risk scenarios, inheritance patterns, and family counseling talking points for genetic counselors.
DownloadSummary of learning characteristics, IEP accommodations, and classroom support strategies for special education professionals.
DownloadComprehensive guide compiled by and for families — valuable for professionals seeking the lived-experience perspective.
DownloadTherapy goals by developmental stage, hypotonia management, and sensory processing strategies from experienced practitioners.
DownloadOverview of augmentative communication approaches used in 5p- Syndrome, including evidence base and device selection guidance.
DownloadA wallet-sized reference card families can carry and hand to emergency responders when seeking care for a person with 5p- Syndrome.
Designed to be carried by the individual or caregiver and handed directly to emergency medical personnel. Covers: communication approach, behavior guidance, medication list format, sedation cautions, and how to contact the family's physician in an emergency.
The card is printable, foldable, and sized to fit in a standard wallet. A family-fillable version allows caregivers to add individual medications, emergency contacts, and specific behavioral notes.
The recommended sequence for families receiving a new 5p- diagnosis — from initial genetic confirmation to community support.
CMA or targeted FISH; parental karyotypes
Echo, audiology, ophthalmology, feeding eval
Developmental assessment; therapy prescription
IDEA Part C services (speech, OT, PT) before age 3
Family connection, peer support, annual conference
Consider connecting newly diagnosed families with the Five P- Society at the time of diagnosis disclosure — not after the referral chain is complete. Peer support from other families has been consistently identified as among the most impactful interventions in the early post-diagnosis period. We can connect families within 24–48 hours of referral.
Our medical advisor and leadership team are available to consult with clinicians, provide case-specific literature, or connect physicians with families they are counseling. We respond to professional inquiries within 48 hours.
Send a Message