The Application of Clinical Genetics (May 2022)
Clinical Importance of aCGH in Genetic Counselling of Children with Psychomotor Retardation
Abstract
Magdalena Pasińska,1 Ewelina Łazarczyk,1 Anna Repczyńska,1 Agnieszka Sobczyńska-Tomaszewska,2 Janusz Zimowski,3 Agata Runge,1 Olga Haus1 1Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, Bydgoszcz, Poland; 2Medical Center “Medgen”, Warszawa, Poland; 3Department of Genetics, Institute of Psychiatry and Neurology, Warszawa, PolandCorrespondence: Magdalena Pasińska, Department of Clinical Genetics, Faculty of Medicine, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, ul. M. Skłodowskiej-Curie 9, Bydgoszcz, 85-094, Poland, Tel/Fax +48 52 585 35 68 ; +48 52 585 36 70, Email [email protected]; [email protected]: The X and Y chromosomes are responsible for the determination and differentiation of the gonads, and their numerical and structural abnormalities may cause the abnormal development of secondary sex characteristics. The presence of abnormalities concerning X chromosome can also contribute to many genetically heterogeneous diseases associated with cognitive impairment and intellectual disability.Purpose: This study shows the effect of aberrations of the maternal X chromosome on the abnormal development of the child.Patients and Methods: Ten women aged 26 to 40 years were consulted in genetic counselling clinic and subsequently subjected to cytogenetic and molecular tests due to abnormal psychomotor development of their children, in whom structural aberrations of the X chromosome had been detected.Results: Two women were diagnosed with changes in karyotype: 46,X,der(X)t(X;Y)(p22.3;q11.2) in one and 46,X,inv(X)(p21.2q13). Five women were diagnosed with microduplications in the short arm of the X chromosome; dupXp22.31 in one, and in four women dupXp22.33. The remaining three women were diagnosed with duplication in the long arm of the X chromosome; dupXq25 in one and dupXq26.3 in two women.Conclusion: Genetic analysis of the X chromosome, based on cytogenetic and molecular methods of the highest available resolution, is extremely important in women with reproductive failure. These methods allow establishing accurately the breakpoints and rearrangements in chromosomes, and assessment of the copy number variation (CNV) can explain phenotypic variability with apparently similar aberrations. A more precise characterization of the alterations is necessary for the correct genetic diagnosis, as well as determination of the carrier status and genetic risk in family members.Keywords: X chromosome, structural aberrations, genetic diagnostics, genetic counseling, intellectual disability
