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Medical Definition of Chromosome 14
1. Trisomy 14 occurs de novo and is due to mosaicism. The distinct phenotype includes postnatal growth retardation, psychomotor retardation, prominent forehead, broad nose, dysmorphic ears, cleft or high arched palate, wide mouth, micrognathia, congenital heart disease, a short neck, asymmetry, abnormal skin pigmentation and hypertelorism. Proximal 14 trisomy (14q1 trisomy) is almost always due to a malsegregation from a parental translocation. Growth and mental retardation are severe and the nose is prominent with broad nasal bridge, the upper lip is long with poorly defined philtrum, the mouth resembles the arc of a circle and the Cupid's bow is replaced by a medial notch. The commissures do not form an acute angle but are ovalised by the sagging of the external portions of the lower lip. Hypotelorism is present and anomalies of the limbs are frequent but longevity is generally not impaired. 14q32 trisomy shows macroglossia, mid-face hypoplasia, hypertelorism, umbilical hernia, hepatomegaly, cardiomegaly and moderately delayed psychomotor development. Seizures are reported. Deletion 14(q11.1q13) is associated with hypotelorism, lack of nasal bridge, flattened nasal tip with no visible septum, wide midline cleft of lip and hard palate, ptosis of upper eyelid and semilobar holoprosencephaly. Ring chromosome 14 shows seizures, mild facial dysmorphism, developmental and moderate growth delay. Chromosome 14 carries the family of genes which encode the heavy chain of immunoglobulins. (05 Mar 2000)
Lexicographical Neighbors of Chromosome 14
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