User:SophiaFerrizzi2020/Heritability of autism

Twinning Risk
It has been suggested that the twinning process itself is a risk factor in the development of autism, presumably, due to perinatal factors. However, three large-scale epidemiological studies have refuted this idea. These studies took place in California, Sweden, and Australia [1]. In Western Australia, the Maternal and Child Health Research Database, which is where all birth records and information is held, was used between the years of 1980-1995 to explore the rates of autism spectrum disorder in the population, especially in twins. This study with the two following were exploring the idea of the -twinning process itself is an important risk factor in the development of autism [1]- they all concluded the same thing that the process of twinning itself is not a risk factor for autism. It is more often than not that both MZ / identical will have autism spectrum disorder -concordance rates of 90% in MZ twins and 0% in DZ twins [24]- it can be explained by the high symmetry among MZ twins compared to that of siblings and DZ twins.[1]

Sex Bias
Autism effects all races, ethnicity, and socioeconomic groups, but more males than females are affected across all cultures [2], the ratios of males- to - females is appropriately 3 to 1[3]. A study was performed analyzing the Autism Genetics Resource Exchange (AGRE database). From this study, it was concluded, that when spontaneous mutation cause autism spectrum disorder (ASD) there is high penetrance in males and low penetrance in females [3][4]. A study in published 2020 explored the reason behind this idea further [5]. It is known that the main difference between males and females is males have one X and one Y sex chromosome whereas female have two X chromosomes. This leads to the idea that there is a gene on the X chromosome that is not on the Y that is involved with the sex bias of ASD [5][2]. In another study, it has been found that the gene called NLGN4 when mutated can cause ASD [6]. This gene (does this gene have a name) and other NLGNs gene are important for neuron communication[2]. This NLGN4 gene is found on both the X (NLGN4X) and the Y (NLGN4Y) chromosome, they are 97% identical.[2][5] When this gene has been studied, most of the mutation that occur are on NLGN4X [2][6]. Research into the difference between NLGN4X and NLGN4Y found that the NLGN4Y protein has poor surface expectations and poor synapses regulations, leading to poor neuron communication [5] [2]. From this, it was concluded that males have a higher- incidences of autism when the mechanism is NLGN4X-associated [2]. This was concluded since females have two X chromosomes if there is a mutation in a X-linked gene, the other X chromosome can be used to compensate for this. Whereas males only have one X chromosome meaning that if there is a mutation in a X-linked gene, that is the copy they have and will be used, this is what leads to the higher incidence of autism in males.[2] [5][6]

Before
It has been suggested that the twinning process itself is a risk factor in the development of autism, presumably due to perinatal factors. However, three large-scale epidemiological studies have refuted this idea. These studies took place in California, Sweden, and Australia. In Western Australia the Maternal and Child Health Research Database; which is were all birth records and information is held, was used between the years of 1980-1995 to explore the rates of autism spectrum disorder, in the population, especially in twins. This study with the two following were exploring the idea of the -twinning process itself is an important risk factor in the development of autism - they all concluded the same thing that the process of twinning itself is not a risk factor for autism. It is more often than not that both MZ / identical will have autism spectrum disorder -concordance rates of 90% in MZ twins and 0% in DZ twins[24]- it can be explained by the high symmetry among MZ twins compared to that of siblings and DZ twins.

Autism effects all races, ethnicity, and socioeconomic groups but more males than families are effected across all cultures, the ratios of males- to - females is appropriately 3 to 1. A study was done analyzing the Autism Genetics Resource Exchange (AGRE database). From this study it was concluded that when spontaneous mutation cause ASD there is high penetrance in males and low penetrance in females. A study in published 2020 explored the reason behind this idea further. It is known that the main difference between males and females is males have on X and one Y sex chromosome where as female have two X chromosomes. This leads to the idea that there is a gene on the X chromosome that is not on the Y that is involved with the sex bias of ASD. In other study it has been found that the gene called NLGN4 when mutated can causes ASD .This gene and other NLGNs are important for neuron communication. This gene is found on both the X (NLGN4X) and the Y (NLGN4Y) chromosome, they are 97% identical. When this gene has been studied most of the mutation that occur are on NLGN4X. Research into the difference between NLGN4X and NLGN4Y found that the NLGN4Y protein has poor surface expectations and poor synapses regulations, leading to poor neuron communication. From this it was concluded that males have a higher- incidences of Autism when the mechanism is NLGN4X-associated-. This was concluded since females have two X chromosomes if there is a mutation in a X-linked gene, the other X chromosome can be used to compensate for this. Where as, males only have one X chromosome meaning that if there is a mutation in a X-linked gene, that is the copy they have and will be used, this is what leads to the higher incidence in males.