Prader-Willi Syndrome

For major depression between monozygotic and dizygotic twins suggest a heritability of about 37%. It is lower than the heritability of bipolar disorder or schizophrenias.

The research argues that PS affects the amygdala, a socioemotional control center in the brain that plays a significant role in the pathogenesis of neurodevelopmental psychiatric disorders. The claim is backed by several studies. PS plays a major role in abnormal psychological, cognitive, and behavioral outcomes in both human and animals. Charil

Parallel to this, the focus on genetics is Particularly convicted in twin studies, which establish a comparison between monozygotic twins that are identical and dizygotic twins, which are opposingly non-identical. This distinction can be identified in Torgersens study, which compared MZ and same sex DZ twins where one proband had an anxiety disorder, and it was discovered that such disorders were 5x more frequent in MZ twin pairs, who mutually shared identical genetics.

1. What is the likelihood that any of their children (sons and/or daughters) will be born with the disorder?

It is believed that faulty genes can cause some disorders that have a psychological effect. A way in which this can be tested is by doing studies on twins as they have the similar genetics. McGuffin et al did a study in 1996 where they compared 109 sets of twins in order to investigate how likely each twin was to develop depression. They looked at the concordance rates for depression in MZ and DZ twins, they expected that MZ twins either both have depression or neither have depression. So therefore its expected to find a higher concordance for depression in MZ twins that in DZ twins. The results showed that if one non identical twin developed depression that there was a 20% likelihood that the other would too, in identical twins this rose to 46%. This study therefore proves that genetics can have a massive impact on abnormality.

Prader-Willi and Angelman Syndrome are two genetic disorders with vastly differing phenotypes linked by missing genetic imprints on the 15th chromosome’s q arm between regions 11 and 13 . While both orders result in mental deficits, their symptoms are otherwise segregated from the other in their entirety. The differences in the disorders are the result of differing DNA methylation patterns present in maternally and paternally inherited DNA. If the deletion occurs in the mother’s DNA, then Prader-Willi Syndrome appears. When the deletion occurs in the father’s DNA, Angelman Syndrome is the result.

Five other gene disorder that contributes to autism are (1) "EN2 (Engrailed 2) involved in cerebellum development. (2) GABR (Gamma Amino Butyric Acid Receptor) regulates brain cell migration. (3) OXTR (Oxytocin Receptor) participating in the response to stress and social skills. (4) RELN (Reelin) involved in neuronal migration in the developing brain. (5) SLC6A4, a serotonin transporter gene” (Johnson, Giarelli, Lewis, & Rice, 2013). As a result of all the researches done several chromosomal loci have been shown to be linked to Autistic Spectrum disorder including those at 2q24-2q31, 7q22-7q31, 7q34-7q36, and 17q11-17q21. Structural chromosomal changes involving deletions and duplication at 7q11, 15q11-15q13, 17p11.2, 22q11.2, and 22q13 have also been associated with forms of autism. However, the most common chromosomal abnormalities currently associated with autism include the fragile X mutation, other sex chromosome abnormalities, and abnormalities of 15q11-q13. “Evidence has shown that duplications of 15q11–q13 have led to higher risks of Autism Spectrum Disorder and developmental and cognitive deficits” (Flashner, Russo, Boileau, Leong, & Gallicano, 2013). Chromosome 15q11-q13.1 region is subject to genomic imprinting, which is an epigenetic process that results in monoallelic gene expression. Duplications lead to autism and are usually maternal in origin. Deletion of the maternal allele of chromosome 15q11-q13 cause Angelman syndrome (AS) a neurodevelopmental disorder

Since 100% concordance was not found, a faulty gene may make the person vulnerable but some kind of environmental factor is needed for the disorder to develop eg. stress. · Over-simplistic and reductionist (using a simpler biological explanation to explain a complex behaviour). The fact that it is difficult to separate nurture (environmental factors) from nature (genes) shows that the evidence is not strong enough for a purely genetic explanation · Natural experiments lack experimenter control over variables eg. the IV (genetic relatedness) could not be isolated from other (possibly confounding) uncontrolled variables eg. environmental experiences, socio-economic backgrounds (class factors).

Aside from genetic studies, it has previously been noted that there are associations between some of the personality traits (which are quantitative in nature and applicable to all human beings) and some categorical psychiatric conditions like depression and schizophrenia [Koorevaar et al., 2013; Guerra et al., 2000]. Identification of the genetic components of personality traits, at the same time as studies are underway to identify genetic components of bipolar disorder and other psychiatric conditions, offer an opportunity to better understand the interactions and components of the biological components that shape psychological experience and psychiatric illness.

The claim of the day was that genetic factors play a strong role in human development that genes alone can determine certain human behavioral characteristics. Plomin focused on behavioral genetics in the 21st century. He discusses quantitative genetics and molecular genetics along with three different directions for genetic research such as developmental genetics, environmental genetics, and multivariate genetics. The greatest need for quantitative genetic research going beyond heritability is asking how much genetic factors are important in behavioral development. The three different directions of

* State how Patria Jacobs’ study of the XYY genotype is tested by Stanley Walzer and Park Gerald’s own study of mental health hospital patients.

If genetic factors are of prime importance then MZ twins should show a higher concordance rate than DZ twins. This is in fact the case, and MZ twins are two to four times more likely to develop schizophrenia than DZ twins. Again, a way of cutting out the environmental factor of upbringing can be seen in adoption studies. Children born from a mother with schizophrenia and separated 3 days after birth are still more likely to develop schizophrenia regardless to their split. Studies have also been carried out to test the importance of environment itself, however very little evidence can be found.

Since it does not affect nutrition and meal absorption at all, it is presumed not to impair children’s growth, while it provokes consistent weight reduction (Velhote et al., 2007).

A genetic disorder, such as DiGeorge syndrome, is an illness caused by one or more abnormalities, which can be passed down through parents, DNA, or mutations. DiGeorge syndrome (DGS) is a rare type of a genetic disorder which is caused by the deletion of chromosome 22. DiGeorge syndrome affects many parts of the body and has a prevalence of 1: 4000

Biological factors such as genetics and biochemical imbalances are highly known as the principal causes to the alterations of the brain chemistry, which could result on the mood becoming unstable. Specialists aim to the genes as principal predisposition to develop the condition, even though there cannot be a detailed genetic analysis and prediction of inheritance, since so many different genes play a part on the implication of this condition. A specific study conducted on twins have confirmed that in fraternal twins (who share approximately 50% of the same genes), if one of the twins develops depression, the other will also be diagnosed with the condition about 20% of the time. In identical twins (sharing the 100% of the genes), however, the rate of concordant diagnoses of depression rises to 76%.