Alzheimer's Disease Genetics Explained

Alzheimer’s Disease (AD) is a chronic degenerative disease of the brain which leads to progressive dementia, which is the loss of the mental faculties of a person. Memory, personality, judgement and reasoning can get severely impaired. The development of AD has a strong genetic component, which may be complicated to understand, but I will try to simplify it here.

There is a gene called APOE. This gene encodes a protein called apolipoprotein E. There are 3 variants of the APOE gene (ε2, ε3, ε4). Each of us inherits 2 variants of the gene, so we all are either ε2/ε2, or ε2/ε3, or ε3/ε3, or ε3/ε4 or ε4/ε4 or ε2/ε4. 

The combination ε4/ε4 has the highest possibility of AD. According to one study, at 85 years of age, people with this combination would have a possibility of 51-52% of developing the disease if male, and 60-68% if female. The combination with the lowest possibility is ε2/ε2, it has a 4-5% possibility of AD if male and 6-8% if female. All the other combinations are in between.

It is important to note that this gene is not the only one associated with AD. If you know your particular combination, it is best to consult a healthcare provider for proper advice.

Marco A. Ramos MD

Further reading here:: http://www.ncbi.nlm.nih.gov/pubmed?cmd=Search&term=9343467

3 Important Things Patients Need to Know About Telemedicine

Technology is improving and advancing fast. What was impossible just a few years ago, is becoming possible now. Nowadays, a physician can see a patient, interview him or her, auscultate, examine the skin, prescribe medications and document in an electronic medical record, without being physically by the patient’s side. 

The first issue that needs to be brought up is the location of the medical act. It has been defined that the medical act occurs where the patient is located. This has consequences regarding licensing and regulations. As it is well known, in the United States, licensing goes state by state, so the physician has to be licensed in the state where the patient is located. This means that, so as the doctor is licensed in the state where the patient is located (and the state medical board is OK with it) the physician can be located anywhere in the world and see, listen and treat a patient.

A second issue is the question of insurance reimbursement. As of today, not all insurance plans reimburse for telemedicine services, although this is increasing by the day. The patients have to be aware if a service rendered by telemedicine will be reimbursed by a particular insurance plan if not paying out of pocket.

The third issue is that there are some specialties that are more ready for telemedicine, than others. For example, Neurology and Psychiatry have been using this services for some years. The surgical specialties (due to the nature of their service) have not quite embraced it yet. It is not impossible to think that in the future, a surgeon might operate remotely, using devices similar to joysticks.

Marco A. Ramos MD

MTHFR mutation. One in 6 people have it. What to do if you have it?

MTHFR mutations are one of the commonly found mutations in genetic testing. If someone is homozygous (carrying one mutation from your father and one from your mother) for the C677T mutation, it may be associated with increased cardiovascular events (heart attacks, strokes), malignancies and birth defects (spina bifida). This does not mean that if someone has the homozygous mutation that person will have a problem. It means that there may be an increased risk.

MTHFR stands for methylenetetrahydrofolate reductase, an enzyme in the metabolic of folic acid. It is also the name of the gene that codes for that enzyme. People with the homozygous mutation have a defective enzyme and  may have some difficulty with the metabolism of folic acid. At the same time, there may be increased levels of homocysteine in the blood, an amino acid associated with thrombotic problems. 

What to do if someone is homozygous for the C677T mutation? Many people find this after testing in commercially available genetic testing. If this mutation is found, a physician or genetic counselor should be contacted. The most likely next step would be an evaluation of homocysteine levels in blood. If normal, the person should be reassured that its risk for cardiovascular events and other problems is probably similar as the rest of the population. If the levels of homocysteine are high, it does not hurt to try to reduce it by having folate supplements and increased vegetables with the diet.

Marco A. Ramos MD

7 Interesting Facts About Vitamin D That You Were Probably Not Aware Of

1. Vitamin D is not a vitamin. It is a hormone. it is structurally related to steroids and has intracellular receptors. It does not function as a cofactor in biochemical reactions like vitamins¹.

2. There is a link between vitamin D deficiency and seasonal affective disorder (SAD), a form of depression which happens more often in winter months². 

3. Vitamin D is produced in the the skin (from the interaction with sunlight) and undergoes 2 modifications, one in the liver and another one in the kidney in order to achieve its full effects.

4. There are receptors for vitamin D, almost in every cellular type of the body. Intestines, bones, brain, kidneys are just examples of organs where vitamin D has an effect.

5. Darker skinned people are more vitamin D deficient than lighter skin people. Also, people living north (or south) of the 30th parallel are more deficient than those who do not.

6. There are significant associations between vitamin D deficiency and cancer, specially colorectal, breast and prostate cancers^3,4,5.

7. There is an association between all-cause mortality and low levels of vitamin D⁶.

References

1. Vitamin D: A Hormone for All Seasons - How much is enough? Understanding the New Pressures. Morris H. The Clinical Biochemist Review. 2005; 26(1): 21–32.

2. Association Between Low Serum 25-Hydroxyvitamin D and Depression in a Large Sample of Healthy Adults: The Cooper Center Longitudinal Study. Hoang, MinhTu T. et al. Mayo Clinic Proceedings. 2011;86(11): 1050-1055

3. Association between vitamin D and risk of colorectal cancer: a systematic review of prospective studies. Ma Y, Zhang P, Wang F, et al. Journal of Clinical Oncology. 2011;29(28): 3775-3782.

4. Vitamin D Deficiency Predicts Prostate Biopsy Outcomes. Murphy AB. Clinical Cancer Research. 2014;20(9): 2289–2299.

5. Vitamin D and Reduced Risk of Breast Cancer: A Population-Based Case-Control Study. Knight JA et al. Cancer Epidemiology Biomarkers Prevention. 2007;16(3):422–429

6. Meta-analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D. Garland CF et al. American Journal of Public Health. 2014;104(8): e43-e50.

Marco A. Ramos MD

3 Reasons Why “Weight Loss Challenges” May Be Unsafe

Weight loss challenges have become a popular way to lose weight. People who consider themselves to be overweight sometimes gather as a group and engage in them in order to lose the extra pounds they consider they have. On some occasions, these activities are promoted by gyms and “fitness” centers. They may consist on exercise routines that may be extreme and in dietary regimens that may be unhealthy. Here are 3 risks that any person participating in these challenges may be exposed to.

1. Risk of muscle injury. Muscle injury (rhabdomyolysis) is a condition that may happen if muscles which have not been subject to exercise regularly are suddenly exposed to it. The main problem with muscle breakdown (besides the pain) is the release of muscle enzymes into the bloodstream. These enzymes are known to be toxic to the kidneys and are known to cause kidney failure.

2. Risk of low sodium concentration. Low sodium in the blood (hyponatremia) can occur in people when they lose body salts through sweat from exercise and drink pure water or low salt-containing fluids. The body, when dehydrated, tries to retain fluid and when a dehydrated person drinks water most of it stays in the body, diluting the remaining sodium concentration. If sodium becomes too low, it can precipitate seizures .

3. Risk of low potassium concentration. Low potassium in the blood (hypokalemia) is known to happen when someone has a prolonged decreased food intake. The main risk of hypokalemia is the development of cardiac arrhythmias that can cause a person to collapse and even to have a cardiac arrest. 

There are other risks of performing unusual physical activity coupled with severe restrictions of food intake. The ones presented in this post are ones that are known to happen and that may pose a risk to a person’s health. Whenever there is a health related issue that needs to be addressed, the primary physician is the best suited professional that can guide a person through the process. He or she should be able to create the best approach for losing weight

Marco A. Ramos MD

3 Common Ways Kidneys Get Damaged Acutely

The kidneys are very delicate organs. As it can be seen in a previous post, they are in charge of many different functions and need to have a good supply of blood at all times in order to perform appropriately. 

1. The most common reason the kidneys get damaged is when the blood supply decreases. This happens when an individual loses fluids through diarrhea, vomiting and does not replenish its fluids with salt-containing fluids. 

2. Certain pain medications, can affect the internal blood flow of the kidneys. If these medications are taken and the body is not adequately hydrated the blood flow to the kidney cells can severely decrease and cause kidney damage. The type of pain medications belong to a category called non-steroidal anti-inflammatory drugs. Common examples of them are ibuprofen, naproxen and ketorolac. Other medications, taken when the body is not well hydrated can also damage the kidneys these include diuretics and blood pressure medications called ACE-inhibitors (examples: captopril, lisinopril, enalapril) and angiotensin receptor blockers (examples losartan, valsartan, irbesartan).

3. Finally, the kidneys can get damaged by a substance that is necessary for certain diagnostic procedures. The use of radiocontrast for coronary angiograpahies or CT scans can damage the kidneys if they are already chronically damaged or if the patient is not adequately hydrated.

There are other causes for acute kidney damage. The post concentrates in the common ones.

All these causes are usually temporary and the faster they are corrected, the better the chances of avoiding longer damage. Whenever there is a change in the level of fluids a body, the balance has to be restored. Do not hesitate to talk to your doctor or go the the closest Emergency Department if you feel at risk.

Marco A. Ramos MD

Is Moderate Alcohol Drinking Good for your Cardiovascular Health?

The answer, of course, is more complicated that everyone thinks. For many years, we have been told, (and as a physician I have told people) that drinking alcohol in moderate amounts is good for the cardiovascular health. This is based on  studies that indeed show a decrease in cardiovascular events (heart attacks, strokes and death) in people who drink alcohol moderately compared to non-drinkers or to heavy drinkers. The basis seemed to be an increase in the HDL “good” cholesterol.

Today, with the availability of genetic testing, scientists have been able to identify a subset of people (15-20% of the population) that may get a huge cardiovascular benefit from drinking alcohol moderately. According to one study, they can reduce the risk up to 80%. What this means is that if someone does not belong to this group, drinking alcohol in moderate amounts probably does nothing to the cardiovascular risk.

What are the potential lessons from this information? The first lesson is that Medicine is an evolving science. As knowledge increases, we physicians will be able to practice better and serve patients better. The second lesson is that individualized care is extremely important. Nowadays we tend to look for “fit-for-all” solutions. The reality is that we are all built differently. 

Marco A. Ramos MD