Loss of chromosome 4q

Posted by Dr. Han Thi Thu Huong - Medical Genetics Division, Vinmec High-Tech Center

Characteristic features of 4q segment loss carriers are abnormal skull shape, short nose with abnormal nasal bridge, low deformed ears, cleft palate, short sternum, growth retardation, intellectual disability from the upper level. moderate to severe, heart defects, heart rhythm disturbances (arrhythmia), genital and urinary organ defects, small body size, small hands and feet, eyes wide apart (hypertelorism), fifth finger and pointed fingernails, decreased muscle tone (hypotonia).
Some children may have small jaws (micrognathia) that lead to difficulty breathing. Possible brain abnormalities (corpus callosum). In some patients, growth retardation and intellectual disability may be present without obvious physical abnormalities, making this pathology difficult to detect.
Some children have psychiatric symptoms such as aggression, verbal hallucinations, mood swings, and delusions. Not all carriers of the 4q deletion mutation have these symptoms, and symptoms can vary from person to person.

Most people are born with 23 pairs (for a total of 46) chromosomes in every cell of the body. Each chromosome consists of a long arm (q) and a short arm (p) separated from each other by a centromere.

4q deletion is a chromosomal disease caused by the lack of a long arm on chromosome 4. This disorder is not usually genetic, but occurs as a de novo of very unknown cause. early in embryonic development.
Symptoms can vary greatly, even within members of the same family. The severity and type of symptoms depend on the size and location of the missing chromosome. Some genes that may be involved include:

4q deletions can be diagnosed with genetic tests including:
Karyotyping: testing for chromosome number and structure. This technique can be used to find large segment losses. FISH (Fluorescent In situ hybridization): a test that detects specific deletion mutations on chromosomes using fluorescently labeled probes. This technique can be used to find small deletions that are hard to see on the karyotype. Array-CGH (Comparative Genome Hybrid) detects all deletions and the size of the missing fragment.

Several other chromosomal disorders may have similar symptoms to a 4q deletion:
Wolf-Hirschhorn syndrome (WHS) is a chromosomal disorder caused by the lack of a short arm of chromosome 4 (one missing). section or monosomy). Major symptoms may include ocular hypertelorism or hooked nose, small head (microcephaly), lower-than-normal ear deformities, growth deficiency, heart defects, intellectual disability and epileptic. Chromosome 11, monosomy 11q is an inherited disorder on the long arm of chromosome 11. Symptoms may include eye distance from one another (hypertelorism), drooping eyelids, crossed eyes (strabismus) and eye positioning. abnormal. Symptoms may also include protruding forehead, wide nose base, upturned nose, short, carp-like mouth, concave chin, deformed ears, intellectual disability. Greig cephalo polysyndactyly syndrome is a rare genetic disorder with symptoms that can include an enlarged head, facial features, and abnormal hands and feet.

Because the 4q deletion mutation affects each individual differently, treatment and interventions must be tailored to the individual needs of the patient.
For heart and bone problems surgery is possible. Children who are slow or are behind in other milestones may need additional physical therapy. Use the drug in cases of epilepsy, acid reflux or growth problems.
Multivitamins, citrus fruits and Coenzyme Q10 are recommended for all children carrying the 4q deletion mutation. Early intervention, special education, and career guidance are especially helpful for children with intellectual disabilities. Genetic counseling is recommended for families with a child carrying a 4q deletion.
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Articles refer to the source: rarediseases.org