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Did you know the lifetime risk for developing alopecia areata is >2%, even with no family history? Alopecia areata is an autoimmune disorder characterized by hair loss on the scalp or other body parts. In people with alopecia areata, the immune system attacks the hair follicles, causing them to shrink and preventing new hair from growing. Studies have shown that people with certain HLA genes are more likely to develop alopecia areata. This suggests that there may be a genetic predisposition for the condition.
Alopecia areata is a health condition that results in massive amounts of hair fall.
Most people with alopecia witness hair fall in small and round patches resulting in a coin-like appearance of bare skin.
While alopecia mostly affects the scalp, it can result in hair fall in other body parts like eyebrows.
It affects as many as 6.8 million people in the United States and 147 million worldwide.
Alopecia is the second most common hair loss condition after androgenetic alopecia and affects men and women equally.
Alopecia isn’t a painful or disabling condition; however, it can change a person's physical appearance, affecting their quality of life and self-esteem.
Most of the research shows that people with alopecia have higher levels of anxiety and depression.
There are two types of alopecia areata:
Research also reports a few rarer forms of alopecia, each with unique hair loss patterns.
The role of our immune system is to fight off unwanted invaders that enter our body, like viruses and harmful bacteria.
In some people, the immune system goes into overdrive and starts attacking the healthy cells in the body, resulting in a group of conditions called autoimmune disorders.
Alopecia, one such autoimmune condition, occurs when the immune system starts attacking the hair follicles.
However, it doesn't destroy the hair follicles, so hair regrowth is a possibility.
The reason why the immune system goes into overdrive is complex and not well understood.
It could be a combination of many factors like hormonal imbalances and genetic changes.
Evidence also supports that environmental factors like stress, physical injury, and illness can result in abnormal immune reactions.
The immune system involvement in alopecia suggests the role of HLA genes in alopecia.
HLA genes to a gene family called the human leukocyte antigen (HLA) complex.
The HLA complex plays a key role in guiding the immune system by helping it differentiate between the body's own proteins and proteins made by foreign invaders.
There are many types of HLA genes, each of which allows the immune system to react to different types of invaders.
Certain changes in these HLA genes can make the immune system confused and result in misidentifying the body's own cells as foreign.
In alopecia, specific HLA gene changes make the hair follicles appear foreign to our immune system.
Other genes involved in inflammatory processes also appear to play a role in alopecia.
Alopecia shares similar genetic roots to other autoimmune conditions.
Therefore, people with alopecia may be at increased risk for conditions like:
People with any of these conditions have an increased risk for alopecia as well.
Several genetic, environmental, and lifestyle factors contribute to alopecia.
As a result, the inheritance pattern is unclear.
However, it is evident that the risk for alopecia is heightened in siblings and children of affected individuals than in the general population.
A family history of other autoimmune conditions also increases the risk of alopecia.
The risk for alopecia increases with:
The primary step in diagnosing alopecia areata is a physical exam to see the pattern of hair loss.
Blood tests can also reveal autoimmune disorders.
The doctor may also perform additional tests to reveal any underlying disorder.
The type of test your doctor may order depends on what they may suspect is causing the problem, which may be based on other symptoms.
Some common medications used to treat children 10 years or younger are corticosteroids and minoxidil.
They are also used in adults with patchy alopecia areata
Complete loss of hair is treated with contact immunotherapy, where the goal is to change your immune system so that it stops attacking your hair follicles.
Is insomnia genetic? According to the Sleep Foundation, the heritability of insomnia is 31-58%, indicating a strong genetic component to insomnia.
In the sample report below, we've attempted to analyze some important genes that increase the risk for insomnia.
You can identify your genetic risk of insomnia by using your 23andMe DNA data and placing an order for the Gene Sleep Report.
Insomnia (also known as sleeplessness) is a common sleep disorder that is characterized by the inability to fall asleep or stay asleep at night, resulting in tired or unrefreshing sleep.
According to the American Psychiatric Association (APA), insomnia is the most common sleeping disorder.
Approximately 30% to 40% of adults in the United States report symptoms of insomnia.
A diagnosis of insomnia needs to meet the following two categories:
This can be caused by variations in biological, psychological, and social factors, which most often result in a reduced amount of sleep.
People with parents or siblings with insomnia have an increased risk of experiencing the condition themselves. This indicates a genetic link to insomnia.
This was further confirmed by a 2018 study that reported that insomnia has a partially heritable basis. In fact, heritability accounts for 31% to 58% of your insomnia risk.
Insomnia also appears to share genetic links with other health conditions.
The researchers also found a strong genetic link between insomnia and type 2 diabetes.
Tissue-specific gene-set analyses showed that insomnia might have higher genetic signals among genes that are usually expressed in the brain.
The functions of these regions of the brain are of relevance to insomnia.
The genetic correlations between insomnia and psychiatric traits were stronger than the genetic correlations between insomnia and other sleep-based characteristics.
The study suggests that, genetically, insomnia resembles neuropsychiatric traits more closely than other sleep-related characteristics.
The MEIS1 gene is a transcription factor that plays a key role in hematopoiesis, endothelial cell development, and vascular patterning.
It also plays a role in neurodevelopment.
Research studies have shown that the reduced MEIS1 levels and function of the gene may contribute to the pathogenesis of sleep-related disorders.
The rs113851554 is a G>T polymorphism located in the MEIS1 gene, which is found to be correlated with multiple sleep disorders.
A study found that the T allele of rs113851554 is associated with an increased risk of developing insomnia symptoms.
Functional study analysis suggested that the rs113851554 in the MEIS1 locus is most strongly associated with insomnia disorder.
A July 2022 study published in Nature Genetics attempted to discover new genetic loci (specific regions in the gene) associated with insomnia.
This was a robust study since it included nearly 600,000 cases and 1.8 million controls.
The study identified 554 risk loci, out of which 364 loci were novel, associated with insomnia.
It also prioritized 289 genes that could help understand the underlying mechanisms of insomnia.
Insomnia is more common in women than in men.
More than one in four women in the United States experience insomnia, compared with fewer than one in five men.
Insomnia is more common in older people than in younger ones.
As many as 50% of older adults complain about difficulty initiating or maintaining sleep.
Medical and psychiatric conditions can increase insomnia risk.
Insomnia is more commonly seen in those with heart disease, asthma, depression, and anxiety than their healthier counterparts.
https://pubmed.ncbi.nlm.nih.gov/30804565/
https://pubmed.ncbi.nlm.nih.gov/26132482/
People have varying eye colors and shades– from dark to light brown, green, hazel, black, gray, and blue.
In fact, a few people have different colors in both their eyes.
Despite these varying eye colors, you will be surprised to know that there are just two pigments in our eyes - brown and red.
The colored part of the eye is called the iris. The iris contains pigment-forming cells called melanocytes, the same ones present in our skin.
These melanocytes produce two pigments – eumelanin (which is brown-black) and pheomelanin (which is red).
The varying shades of eye color depend upon the amount of pigment produced.
For example, people with dark eye color have a large amount of brown-black eumelanin, whereas those with light blue eyes have very little pigment.
Image: Is Eye Color Genetic: Types of Melanin Pigment
Just like fingerprints, eye color is unique to an individual and is genetically determined.
A genome-wide association study identified 115 genetic variants associated with eye color.
Two genes located close to each other on chromosome 15– OCA2 and HERC2 are said to play an important role in eye color determination.
Though the OAC2 gene influences 75% of eye color, other genes also play a role in melanin production.
The OAC2 gene gives instructions to produce P protein that helps in the maturation of melanosomes (cellular structures that make and store melanin).
The P protein influences the amount of melanin in the iris.
Common changes (called variations or polymorphisms) in the OAC2 gene may reduce the amount of P protein produced.
People with less P protein have less melanin in their eyes.
This also means they may have blue eyes instead of brown.
The HERC2 gene is located very close to the OAC2 gene.
A part of the HERC2 gene is also called intron 86. This region regulates the activity of the OAC2 gene.
At least one polymorphism in the HERC2 gene area has been shown to reduce the OAC2 gene and decrease P protein production.
This results in less melanin in the iris and light-colored eyes.
Though eye color is genetically-determined, it is also an inherited trait.
For a long, scientists believed that a single gene was responsible for an individual’s eye color. However, the inheritance of eye color is far more complex.
The study of inheritance and genetics of eye color are still in the nascent stages.
Image: Is Eye Color Genetic: Inheritance of Eye Color
Source: https://www.nature.com/articles/s41433-021-01749-x
It is impossible to predict a baby's eye color with 100% certainty.
But with certain genetic rules, it is possible to make a fair guess.
For example, the brown eye is a dominant trait - this means it can hide traits of green and blue eyes.
To find the possibility of recessive traits, it's helpful to know the grandparents' eye colors.
For example, if the mother has blue eyes and her entire family has blue eyes and the father has brown eyes with his mother and father with brown and blue eyes, the kid will have a 50/50 chance of having a blue-eyed or brown-eyed child.
| Probability of Eye Color | ||||
| Parent 1 | Parent 2 | Blue | Green | Brown |
| Blue | Blue | 99% | 1% | 0% |
| Blue | Green | 50% | 50% | 0% |
| Blue | Brown | 50% | 0% | 50% |
| Green | Green | 25% | 75% | 0% |
| Green | Brown | 12% | 38% | 50% |
| Brown | Brown | 19% | 7% | 75% |
Source: https://www.verywellhealth.com/genetics-of-eye-color-3421603
https://medlineplus.gov/genetics/understanding/traits/eyecolor/
https://www.verywellhealth.com/genetics-of-eye-color-3421603
https://www.gbhealthwatch.com/Trait-Eye-Color.php
A 2020 study identified 5 regions of the genome linked to nicotine dependence.
In the sample report below, we've attempted to analyze some important genes that increase the risk for nicotine dependence.
You can identify your genetic risk of insomnia by using your 23andMe DNA data and placing an order for the Gene Nutrition Report.
Nicotine is a nitrogen-containing chemical and is a highly addictive substance. It is mainly found in tobacco and is primarily consumed by inhaling the smoke of tobacco cigarettes.
Nicotine produces ‘pleasurable and pleasing’ effects on the brain.
With regular smoking, you tend to get used to these positive feelings. Going without a smoke can make you experience unwanted effects - this indicates nicotine dependence.
According to the CDC, smoking is the leading cause of preventable death in the U.S.
A study suggested that smoking is responsible for 1 in every 5 deaths in the U.S.
The symptoms vary amongst individuals and also differ based on the level of dependence. Some signs to watch out for include:
The addictive quality of nicotine is what causes nicotine dependence.
Nicotine triggers the release of the happy hormone dopamine.
This pleasure response is what smokers chase after.
Smoking also increases the heart rate, boosting the noradrenaline hormone. The increased hormone levels enhance mood and concentration.
People who smoke nicotine start craving the dopamine rush. When they abstain from smoking for a few hours, their hormone levels start to drop, and they start to experience undesired effects like irritability and anxiety.
Nicotiana tabacum is the type of nicotine found in tobacco plants. The tobacco plant has been used for its medicinal benefits for at least 200 years.
“It is thought that Christopher Columbus discovered tobacco while exploring America for the first time.
Using tobacco for smoking started and spread rapidly over the 1600s. When it was introduced in Europe, some saw its medicinal purpose, while others viewed it as a toxic, addictive substance.
Tobacco usage exploded when cigarette-making machines were introduced in the 1880s.
Only in 1964 a study established a link between smoking and heart and lung cancer was published. 30 years later, in 1994, the U.S. FDA recognized nicotine as a drug with addictive properties.
Finally, only in 2009 the Supreme Court granted the FDA control to establish some nicotine regulations.
A person may have smoked cigarettes in his youth and would’ve had no trouble stopping it after.
Another person may enjoy recreational smoking but not feel the need to smoke a few every day, and a few others may smoke a pack a day and cannot seem to quit this habit.
So, what contributes to these differences in smoking patterns? Why are the pleasure-inducing effects of nicotine evident in some and not in others?
Some studies have revealed that the differences in response to nicotine can be attributed to changes in some genes that produce receptors to which nicotine binds.
Let’s dilute this further. Nicotine has a similar structure to the neurotransmitter acetylcholine.
Acetylcholine is known to influence memory, arousal, attention, and mood.
Nicotine binds to a type of acetylcholine receptor called the nicotine acetylcholine receptors or nAch. nAch receptor has 5 subunits.
These subunits are produced by certain genes.
Any changes in these genes can alter the structure of the subunits, which in turn can alter the nAch structure.
These alterations modify how you respond to nicotine.
The CHRNA5 gene contains instructions for producing the α5 subunit of the nAch receptor.
Certain changes or mutations in this gene alter the α5 subunit and makes the nAch receptor channels more/less sensitive to nicotine.
rs16969968
rs16969968 is an SNP in the CHRNA5 gene. It influences the pleasurable effects of nicotine.
The A allele has been associated with “enhanced pleasurable responses” to a person’s first cigarette.
The A allele carriers are at an increased risk for nicotine addiction compared to the G allele carriers.
Interestingly, the A allele has also been associated with a lower risk for cocaine dependence!
The CHRNB3 gene contains instructions for producing the β3 subunit of the nAch receptor.
This gene has been identified to predispose an individual to nicotine addiction.
rs10958726
rs10958726 is an SNP in the CHRNB3 gene. The T allele of this SNP has been associated with an increased risk of nicotine dependence.
Several other genes like CHRNG, CHRNA4, CYP2B6, and FMO also influence the risk of nicotine dependence.
Age: According to a study, the chances of developing nicotine dependence are higher when the age of onset of smoking is before 21, especially between 18-20 years.
Peers: People who grow up with smoking parents or spend more time around friends who smoke are more likely to smoke and may eventually develop nicotine addiction.
Substance usage: People who consume alcohol or drugs are more likely to become nicotine dependent. The reverse relationship is also true! In fact, according to a study conducted to evaluate concurrent use of alcohol and cigarettes, approximately one-third of current drinkers smoked, whereas approximately 95 percent of current smokers used alcohol.
Mental illness: People with mental troubles like depression, PTSD, or schizophrenia are more likely to be smokers than others. A study examining depression and nicotine dependence from adolescence to young adulthood reported that depression is a prominent risk factor for nicotine dependence. The adolescent and youth population exhibiting depression symptoms constitute an important group that requires smoking intervention.
Using tobacco can lead to grave health complications. Nicotine dependence has been tied to an increased risk of various health conditions.
Tobacco smoking, to date, remains the most established contributor to lung carcinogenesis or lung cancer.
Recent studies suggest that nicotine, in small quantities, accelerates cell growth and, in large quantities, becomes toxic to cells.
Nicotine also decreases the levels of CHK2, a protein that acts as a tumor suppressor.
Further, it lowers the effects of anti-cancer treatments. Smoking contributes to 30% of all deaths due to cancer!
Cigarette smoking remains the leading cause of COPD in the U.S.
A CDC analysis revealed that the prevalence of COPD in adults was 15.2% among current cigarette smokers, compared to 2.8% among adults who never smoked!
Smoking causes damage to the heart and blood vessels.
It also alters your blood chemistry, contributing to plaque build-up. In the U.S., smoking accounted for 33% of all deaths caused due to cardiovascular diseases.
Research shows that nicotine influences the activity of the pancreas.
The usage of nicotine leads to decreased production of insulin by the pancreas.
Thus, the blood sugar levels are poorly regulated, leading to diabetes.
Smokers with diabetes may require higher insulin doses to keep their blood sugar levels in check.
Tobacco smoking during pregnancy increases the risk of morbidity and mortality in newborns.
Nicotine damages the developing lungs and brain of the fetus.
Common birth defects caused due to nicotine are cleft lip and cleft palate.
Nicotine Replacement Therapy (NRT) has been suggested for pregnant women who cannot quit smoking.
However, the safety of NRT to the developing fetus has not been well-documented yet.
Nicotine withdrawal is the set of symptoms one experiences upon stopping tobacco usage. It can start as early as 30 minutes from the last usage.
The range and severity of symptoms can depend on how long the person has been smoking and how often they have smoked.
Owing to the withdrawal symptoms, quitting smoking can be very challenging.
The following are the basics of any de-addiction program which can help you overcome nicotine addiction.
Other specific ways can help you gradually become nicotine-independent.
It is the process of administering the nicotine that your brain demands more safely by avoiding all the other harmful substances present in cigarettes.
This also provides relief from the withdrawal symptoms.
NRT supplies lower doses of nicotine at slower rates. Some of the commonly available NRTs include:
All of these are generally available over the counter and do not require prescriptions.
Certain medications do not contain nicotine but are designed to produce the same effects of nicotine on the brain.
They help decrease cravings and alleviate other withdrawal symptoms. Some examples of these medications include Chantix and Zyban.
Important note
In 2009, the FDA mandated the makers of such medications to put a black box, warning the users about the possible dangerous psychological effects, including agitation, depression, and suicidal thoughts.
CBT trains smokers to cope with the symptoms of withdrawal. CBT has achieved twice the success rate when quitting smoking (compared to people who didn’t receive CBT).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2928221/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2928221/
https://www.ncbi.nlm.nih.gov/pubmed/18783506?dopt=Abstract
https://www.snpedia.com/index.php/Rs16969968
https://www.ncbi.nlm.nih.gov/pubmed/18519132?dopt=Abstract
https://www.ncbi.nlm.nih.gov/snp/rs10958726
https://www.cdc.gov/pcd/issues/2020/19_0176.htm
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1931414/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4314348/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4553893/
https://www.cdc.gov/mmwr/volumes/68/wr/mm6824a1.htm
https://www.ncbi.nlm.nih.gov/books/NBK53012/
https://www.sciencedaily.com/releases/2019/10/191016131214.htm
https://medlineplus.gov/ency/article/007438.htm
Answering whether PTSD (post-traumatic stress disorder) is genetic can be challenging.
While studies suggest that genes may play a role in 30% of cases, the complex interplay between genes and the environment makes it difficult to pin down specific gene variants.
In addition, PTSD often occurs alongside other mental illnesses, making it even harder to tease apart the relative contributions of genetics and environment.
One way scientists have tried to untangle the role of genes in PTSD is through genome-wide association studies (GWAS).
These studies look for small variations in the DNA of people with and without PTSD to identify gene variants that might be linked to the disorder.
PTSD is a mental and behavioral disorder that can occur after someone experiences or witnesses a traumatic event.
Some of the common PTSD are flashbacks, nightmares, trouble sleeping, and feeling angry or irritable.
For some people, the symptoms get worse and last for a long time, even years.
PTSD affects how a person thinks and feels and may present as a change in their personality.
When a person experiences or witnesses a traumatic event, it can have a lasting effect on their mental health.
PTSD symptoms can appear soon after the traumatic event or may not appear until months or even years later.
PTSD can cause a person to feel scared, anxious, and isolated. It can also lead to physical health problems.
If you are experiencing symptoms of PTSD, it is important to seek help from a mental health professional.
A terrifying event can trigger PTSD.
PTSD can occur after any dangerous or scary encounter, such as a car accident, natural disaster, terrorist attack, or sexual abuse.
It can also occur after witnessing someone else experience a traumatic event or learning that a loved one has been harmed.
A report from Harvard University shows that 30 percent of PTSD cases were explained by genetics.
According to the study, identical twins with smaller hippocampus were more likely to develop PTSD following tragic events.
The study further reported that symptoms of PTSD overlap with those of other psychiatric conditions like panic disorder and generalized anxiety disorder.
Genes that play a role in creating "fear memories" could be targets for potential therapeutic interventions for PTSD.
In 2019, scientists from the University of California San Diego School of Medicine and more than 130 additional institutions participating in the Psychiatric Genomics Consortium conducted the largest and most diverse genetic study of PTSD to date.
They used a genome-wide association study (GWAS) to study genetic data points across 200,000 people.
According to the authors, 5-20% of the variability in PTSD risk following a traumatic event.
The study team also reports that, like other psychiatric disorders, PTSD is highly polygenic - it is associated with thousands of genetic variants, each making a small contribution to the disorder.
Karastan Koenen, the senior author, also said, "based on these findings, we can say with certainty that there is just as much of a genetic component to PTSD risk as major depression and other mental illnesses."
After evaluating certain symptoms, a qualified healthcare professional can help with PTSD diagnosis.
To be diagnosed with PTSD, the following criteria should be met:
These symptoms also must:
Psychotherapy and medications are commonly used treatment options for PTSD.
Researchers have identified a number of genes associated with Alzheimer's disease.
While some genes increase your risk for developing Alzheimer's (risk genes), others are causal (deterministic).
In the sample report below, we've attempted to analyze some important genes that increase the risk for Alzheimer's.
You can identify your genetic risk of Alzheimer's by using your 23andMe DNA data and placing an order for the Gene Health Report.
According to the Alzheimer’s Association, Alzheimer’s disease is “a type of dementia that causes problems with memory, thinking and behavior.”
The disease is named after Dr. Alois Alzheimer, who first described it in 1906.
Symptoms usually develop slowly and worsen over time, eventually interfering with daily tasks.
It is caused due to a combination of different factors.
The risk for Alzheimer's disease has a genetic component to it.
While there is no current cure for Alzheimer’s, treatments are available to help manage the symptoms.
There are two types of Alzheimer’s Disease: early-onset and late-onset.
Early-onset Alzheimer’s is a rare form of the disease that typically affects people in their 40s and 50s.
Late-onset Alzheimer’s is the more common form of the disease and typically affects people over the age of 65.
Both forms of Alzheimer’s are progressive, meaning they worsen over time.
Early-onset Alzheimer’s progresses more rapidly than late-onset Alzheimer’s, but both forms ultimately lead to dementia.
The cause of Alzheimer's is still largely unknown, but scientists believe it is linked to a combination of genetic, lifestyle, and environmental factors.
One of the main theories behind the development of Alzheimer's disease is the build-up of abnormal proteins (amyloid plaques and tau proteins) in the brain.
This build-up damages the nerve cells and prevents them from communicating with each other.
When the brain cells get affected, the levels of neurotransmitters or brain chemicals used to send messages in the brain decrease.
One of these brain chemicals, called acetylcholine, is involved in learning and memory.
In the brains of people with Alzheimer’s, the levels of acetylcholine are lower.
As there is more and more plaque build-up, the brain cells die, causing the brain to shrink.
Although there is no cure for Alzheimer's, treatments are available to help slow its progression and improve the quality of life for those with it.
Both types of Alzheimer’s have a genetic component to it.
While some genes increase the likelihood of a person developing the condition, others guarantee disease development.
Most people with Alzheimer’s have the late-onset type.
The most commonly identified gene for this type is the ApoE gene, which is involved in making a protein that helps carry cholesterol and other types of fat in the bloodstream.
ApoE comes in different forms determined by the alleles e2, e3, and e4.
About 25 percent of people carry one copy of APOE ɛ4, and 2 to 3 percent carry two copies.
Some other genes that influence late-onset Alzheimer’s risk are (list not exhaustive):
10% of all people with Alzheimer’s have the early onset type.
Research has identified 3 genes associated with this condition.
The APP Gene
The APP gene contains instructions for producing the amyloid precursor protein.
It is present throughout the body, mainly in the brain and spinal cord.
This protein is important for brain development and helps nerve cell movement and communication.
10-15% of early-onset Alzheimer’s is due to mutations in the APP gene.
The PSEN1 Gene
The PSEN1 gene contains instructions for producing presenilin 1, a protein that is a part of a larger complex called the gamma-secretase.
This complex plays a role in the fragmentation of proteins, especially the amyloid precursor protein.
Mutations or changes in the PSEN1 gene can result in abnormal chopping of the APP, resulting in amyloid plaque buildup, an important cause of Alzheimer’s.
The PSEN2 Gene
The PSEN2 gene produces presenilin 2 and works in a similar fashion to the PSEN1 gene to contribute to Alzheimer’s risk.
There is no cure for Alzheimer’s disease; however, there are medications that can help to slow the progression of the disease and manage symptoms.
The U.S. Food and Drug Administration (FDA) has approved several medications for treating Alzheimer’s, including cholinesterase inhibitors and memantine.
These medications can help improve cognition, memory, and communication skills and reduce behavioral problems.
Clinical trials are ongoing to test new potential treatments for Alzheimer’s disease.
