Chromosome 18p duplication
- Duplication 18p
- Trisomy 18p
- 18p duplication
- 18p trisomy
- Partial trisomy 18p
Your QuestionWhat are some of the signs or symptoms associated with trisomy 18p? What are some of the behavioural characteristics of this syndrome if any? What are some treatment options for an adolescent with this syndrome, ASD (autism spectrum disorder), and no intellectual disability displaying challenging behaviours?
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Trisomy 18p has rarely been reported. According to Mabboux et al. (2007) only 21 cases have been documented in the medical literature. The signs and symptoms vary greatly from person to person and is characterized by mental retardation, foot or hand anomalies and craniofacial anomalies. Treatment is based on the specific findings present.
According to Rodríguez (2007) et al., all the cases of trisomy 18p show a noncharacteristic facial appearance and a mental development ranging from normal to moderate impairment.
Examples of Cases:
- Taylor et al. (1975) - female with no physical or mental abnormalities
- Takeda et al. (1989) - female without mental retardation
- Wolff et al. (1991) - mother and daughter were of normal intelligence and had a short pinky finger on both of their hands
- Moog et al. (1994) - mother and son; mother had developmental delay and learning disabilities and son had moderate mental retardation and slight craniofacial anomalies
- Li et al. (1998) - male with developmental delay, hypotonia (low muscle tone) and minor physical abnormalities
Some have suggested that several of the cases of trisomy 18p reported in the medical literature of people with signs and symptoms represent cases in which other chromosomal abnormalities not yet identified may explain the signs and symptoms present, suggesting that pure trisomy 18p results in little, if any, signs and symptoms. As more advanced techniques for identifying chromosomal abnormalities become available, we will learn more about the signs and symptoms associated with trisomy 18p. It is possible that some cases of trisomy 18p are being missed because they do not have any signs and symptoms and are of normal intelligence.
- Mabboux P, Brisset S, Aboura A, Pineau D, Kourbi V, Joannidis S et al. Pure and Complete Trisomy 18p Due to a Supernumerary Marker Chromosome Associated with Moderate Mental Retardation. American Journal of Medical Genetics Part A. 2007;
- Rodríguez L, Liehr T, Mrasek K, Mansilla E, Martínez-Fernández ML, Garcia A, Martínez-Frías ML. Small Supernumerary Chromosome Marker Generating Complete and Pure Trisomy 18p, Characterized by Molecular Cytogenetic Techniques and Review. American Journal of Medical Genetics Part A. 2007;
- Schinzel A. Catalogue of Unbalanced Chromosome Aberrations in Man. New York: Walter de Gruyter; 2001;