The der(22) syndrome shows increased gene dosage at 22q11 with features that overlap with the cat-eye syndrome (CES).


Chromosome Location: 22q11


Genetic changes associated with the phenotype:

(1) supernumerary chromosome +der(22)t(11;22)(q23;q11)

(2) supernumerary chromosome +der(22)t(11;22)(q23;q11) plus balanced translocation (11;22)


A parent who is a carrier for a balanced t(11;22)(q23;q11.2) translocation can have an offspring with der(22) if there is a 3:1 meiotic non-disjunction.


Clinical findings may include:

(1) anal stenosis or atresia

(2) pre-auricular skin tags or pits

(3) mental retardation

(4) micrognathia

(5) variable congenital heart disease

(6) variable genitourinary anomalies (hypospadias, renal agenesis, vesiculourethral reflux, etc)

(7) cleft or high-arched palate

(8) microcephaly

(9) failure to thrive

(10) ear anomalies


Features of CES not seen with der(22):

(1) ocular colobomata

(2) microphthalmia

(3) total anomalous pulmonary venous return


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