* Centre hospitalier Le Mans, France.
** Inner Vision Women's Ultrasound, Nashville, Tennessee, USA;
Synonym: 5p- (5p minus) syndrome, Chromosome 5p deletion syndrome, Cat cry syndrome.
Incidence: 0.2 - 0.5: 10,000 live births
Introduction
Cri-du-chat syndrome is a condition in which a piece of a short arm of chromosome 5 is missing. It is one of the most common syndromes caused by a chromosomal deletion. The affected neonates have a typical, high-pitched cry resembling the cry of the cat, often caused by maldeveloped larynx. The infants show developmental delay, hypotonia, microcephaly. Their typical features include: hypertelorism, low-set ears and small jaw. The congenital heart defect maybe associated with this condition. The size of deleted piece of chromosome 5 determines the severity of the mental retardation. The gene which is thought to be mainly responsible for the developmental delay is CTNND2.
Most of the cases are caused by new mutations, de novo deletions.
Life expectancy is normal, unless there is some serious associated clinical condition.
Ultrasound findings
- Microcephaly
- Facial dysmorphic features: hypertelorism, micrognathia, low-set ears
- Intrauterine growth restriction
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Single palmar crease
- Cardiac defects (ventricular, atrial septal defect, patent ductus arteriosus, tetralogy of Fallot)
Occasional abnormalities associated with this condition may include: Cleft lip and palate, myopia, optic atrophy, preauricular skin tag, bifid uvula, clinodactyly, absent kidney and spleen, cryptorchidism and hemivertebra.
Case report
This is a case of a 31-year-old G4 P3 with non-contributive family and personal history. Her first and second trimester scan were both normal. The triple test was normal as well.
The ultrasound scan at 33 weeks showed a male fetus with normal biometry, aside from the femur bone that was a little short. The brain scan showed mildly dilated anterior horns of the lateral ventricle, short corpus callosum (31 mm), short transverse diameter of the cerebellum. There was an unilateral cleft lip as well. We suspected pontocerebellar atrophia and patient was referred for fetal MRI which confirmed our findings. Amniocentesis was suggested based on the ultrasound findings. Patient agreed with the procedure and the karyotype was abnormal and showed missing short arm of chromosome 5, 5p- characteristic for Cri-du-chat syndrome. Patient decided for the pregnancy termination.
Images 1,2: Axial view of the fetal brain, anterior horns are slightly dilated.