| Abstrakt: |
Background: Intellectual disability (ID) consists of a broad range of disorders characterized by low general intellectual functioning (IQ below 70). ID etiologic causes are heterogeneous, ranging from environmental to chromosomal and monogenic conditions. Although many autosomal genes responsible for ID are expected, only a small number of these have been identified, and up to now most progress has been made in X-linked translocation ID area; but many autosomal genes play a crucial role in the development of a central nervous system. Any change which leads to lose or reduce the function or changes the expression of them; high or low, even have a damaging effect on the functional protein might lead to different phenotypes like developmental delay, growth retardation, or intellectual disabilities. Result & conclusion: In this paper, we discuss the importance of balanced chromosomal translocations in the cause of newborn intellectual disabilities. Balanced translocation is the result of breaking off two chromosomes and reattaching in a way that the sections of two chromosomes have switched places. These rearrangements are found as de novo events in 1/2000 live births and give rise to some congenital anomalies which are the product of submicroscopic deletions, duplications, inversion or disruption, activation, or inactivation of a gene or different genes located at or near the breakpoints in the basepair level. These apparently balanced translocations due to positional effect lead to abnormal phenotype. Conclusion: Cryptic genomic imbalances which cause mentality are very rare conditions but new technologies like NGS long-read genome sequencing could detect breakpoint effects on live birth health and discover a new way for prenatal diagnosis. [ABSTRACT FROM AUTHOR] |
