Genetic counseling: Cri-du-chat syndrome - deletion 5p

Cri-du-chat syndrome - deletion 5p

Contracting

 * Introduction
 * Ask about what their main concerns are
 * Explain that we will update medical and developmental history since her last visit to genetics
 * Doctor will perform physical examination
 * We will discuss your concerns and any recommendations we have

Interim History
(Follow form, but specifically ask about list of potential health problems located below Overview)
 * Cri du chat is a syndrome that is associated with a deletion of the short arm of chromosome 5
 * French for "cat's cry"
 * incidence is 1:50,000 (Van Buggenout et al, 2000 ) may be as high as 1:20,000 (OMIM)

Characteristic features

 * usually suspected at birth based on characteristic monochromatic, high-pitched cry
 * poor suck, vomiting, failure to thrive, respiratory distress and jaundice present in 60-92%
 * microcephaly
 * round face
 * hypertelorism
 * epicanthal folds
 * down-slanting palpebral fissures
 * low-set ears
 * micrognathia
 * psychomotor retardation
 * high arched palate
 * as individuals with 5p deletion get older change of phenotype is noted and it is less striking and harder to diagnose (face lengthens, face becomes "coarse", prominent supra-orbital ridges, deep-set eyes, hypoplastic nasal bridge, severe dental malocclusion, relatively large mouth, and full lower lip)

Potential health problems

 * several cardiac anomalies described in a small number of patients (ASD, VSD, tetralogy of fallot and PDA)
 * cleft palate (rare)
 * gastrointestinal abnormalities include malrotation and Hirschprung disease
 * teeth abnormally erupted
 * Apnea
 * Strabismus
 * Minor vision problems
 * Gastric reflux
 * Chronic constipation (well managed in most cases)
 * Colic
 * Frequent ear and upper respiratory infections
 * Scoliosis
 * Sleep disorders
 * Saliva control problems (if not resolved during childhood surgery can help correct)
 * Minor hearing impairment

Growth

 * compared with the standard population, most children with cri-du-chat syndrome are small at birth
 * as they grow most have significant microcephaly
 * weight compromised for age
 * slow growth frequently observed
 * may be evidence of intrauterine growth retardation

Life expectancy

 * Difficult to predict
 * 10% mortality in first year due to respiratory or cardiac complications
 * Believed that if no major health problems present life span would be in normal range

Learning

 * study of 26 children ages 6 yr. 4 mths and 15 yr 5 mths
 * moderate to severe learning difficulties and developmental delay are usually observed
 * 24 were in severe learning disability range
 * better receptive than expressive language
 * study of seven patients
 * 6 severe or profound MR
 * 1 mild MR
 * Language comprehension may not be as impaired as language production
 * Clear benefit shown in those children that received early intervention services compared to those that did not
 * Developed many self-care skills
 * Communicate through short sentences, words, signs, or gestures

Behavior

 * study examined the range, distinctiveness, and correlates of maladaptive behavior in 146 subjects using the Aberrant *Behavior Checklist as a standardized measure
 * Hyperactivity was the most significant and frequent problem in the sample
 * Subjects also showed aggression, tantrums, self-injurious behavior
 * some of these problems were more pronounced in individuals with lower cognitive-adaptive levels, as well as in those with histories of previous medication trials
 * Autistic-like features and social withdrawal were more characteristic of individuals with translocations as opposed to deletions, even when controlling for the lower adaptive level of the translocation group
 * head banging, hitting the head against body parts, self-biting and rumination are the most frequently occurring behaviours in CCS
 * Aggressive behaviour was reported for 88%, with a statistically significant negative correlation between age and the number of aggressive behaviors reported
 * Study of 7 older patients most had periods of destructive behavior, self mutilation and aggression
 * Other reported behaviors include:
 * Repetitive movements
 * Obsessive attachment to objects
 * Hypersensitivity to sensory stimuli
 * Feeding and sleeping problems
 * Mood disorders

Genetics

 * 85% are sporadic deletions (recurrence risk? I'm guessing not greater than general population unless possibility for germline mosaicism)
 * 10-15% are familial (usually parental translocation rarely a familial inversion)
 * PARENTAL CHROMOSOMES SHOULD BE DONE SO ACCURATE RECURRANCE RISKS CAN BE CALCULATED
 * Gene that makes Delta-catenin (an adherens junction protein involved in cell motility and expressed early in neuronal development)
 * delta-catenin maps to a specific region in 5p15.2 that has been implicated in the mental retardation phenotype
 * strong correlation between the hemizygous loss of delta-catenin and severe mental retardation

Genotype-phenotype correlation

 * Patients show phenotypic and cytogenetic variability
 * Genotype-phenotype correlation in 62 patients with terminal deletions highlighted a progressive severity of clinical manifestation and psychomotor retardation related to the size of the deletion (Mainardi et al, 2001). Whereas other study reported no correlation with size of deletion and severity in 50 patients (Marinescu et al, 1999).
 * The analysis of seven patients with interstitial deletions and one with a small terminal deletion confirmed the existence of two critical regions, one for dysmorphism and mental retardation in p15.2 and the other for the cat cry in p15.3
 * study lends support to the hypothesis of a separate region in p15.3 for the speech delay
 * One family with deletion 5p where breaking point is slightly distal to 15.3 showed only

Patient resources/ references

 * 5p- Society (Cri-du-Chat) -- support group
 * 11609 Oakmont
 * Overland Park, KS 66210
 * Phone: (913) 469-8900
 * E-mail: fivepminus@aol.com
 * Web Site: http://www.fivepminus.org/
 * Conference in SLC Aug 15-19, 2002


 * Chromosome Deletion Outreach
 * P.O. Box 724
 * Boca Raton, FL 33429-0724
 * E-mail: cdo@worldnet.att.net
 * Web site:members.aol.com/cdousa/cdo.htm
 * Cri Du Chat Support Group of Australia Inc.
 * Email: info@criduchat.asn.au 
 * Web: http://www.criduchat.asn.au