Chromosome 4, Monosomy 4q is a chromosomal disorder caused by a partial deletion of the long arm of chromosome 4. The patient may have an extremely prominent forehead (frontal bossing), enlargement of the back part of the head, low placement of ears, short broad hands and feet, unusually small size associated with slow or delayed growth, congenital heart defects, and possible mental retardation.
Patients with Chromosome 4, Monosomy 4q may have the following symptoms: abnormal skull shape, short nose with abnormal bridge, low-set malformed ears, cleft palate, small jaw, short breastbone, poor or delayed growth, moderate to severe mental retardation, heart defects, defective urinary and reproductive organs (genitourinary defects), small size, small hands and feet, unusually wide-set eyes (hypertelorism), a pointed fifth finger and nail which is very characteristic of this disorder, and diminished muscle tone (hypotonia). There may be abnormal brain development (agenesis of corpus callosum). In some cases, delayed growth and mental retardation may be present without obvious physical abnormalities, making it difficult to diagnose this disorder.
Chromosome 4, Monosomy 4q is caused by a partial deletion of the long arm of chromosome 4. The severity and type of abnormalities depend on the size and location of the missing chromosomal piece. Whether it is interstitial (situated between other parts of the chromosome) or terminal (on the end part of the chromosome) usually determines the symptoms and severity of the disorder.
Chromosome 4, Monosomy 4q is a rare disorder that is present at birth. It affects males and females in equal numbers.
For patients of Chromosome 4, Monosomy 4q, special education, physical therapy, and vocational services may be of benefit. Genetic counseling may be of benefit for patients and their families. Other treatment is symptomatic and supportive.
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