Cri du chat

Question 1

What are the symptoms of Cri du chat?

Answer 1

Cat-like cry (newborns)
-only first weeks of life due to outgrowing this symptom
Low birth weight
Microcephaly
Hypotonia
Distinctive facial features
-widely spaced eyes
-crossed eyes
-low set ears
-normally small jaw
-occasionally, improper alignment of the upper and lower teeth
Psychomotor disabilities
Intellectual disabilities

Question 2

What genes are involved in Cri du chat?

Answer 2

Partial deletion of the short arm (p) of chromosome 5

Loss of CTNND2 gene–> associated with severe intellectual disabilities

Question 3

What is the inheritance pattern of Cri du chat?

Answer 3

Most cases are not inherited–> de novo mutation

Question 4

What is the phenotype of the heterozygous?

Answer 4

Since it usually happens through de novo mutations, there is not a dominant or recessive allele