SICKLE CELL ANEMIA: CHROMOSOME AND INHERITANCE

Chromosome & Inheritance

Mode of inheritance

The Marfan syndrome inheritance is known to have an autosomal dominance pattern. “Autosomal refers to the fact that the gene causing the disorder does not occur on one of the sex chromosomes. Therefore, the sex of the affected parent and the sex of the child have nothing to do with who is affected. Dominant refers to the fact that only one of the two copies of the causative gene needs to carry the mutation for the disorder to be present.”[i] Even if you inherited one normal gene from your mother and a mutated gene from your father, you will still carry the symptoms of the disease. If a sibling or a relative shows no symptoms of the Marfan syndrome, he or she is more unlikely to have the disease and will not have the ability to pass it on to his or her child.

Fibrillin-1 gene instructs our cells to produce the protein fibrillin for the making of connective tissues in the human body system. Mutations in the Fibrillin-1 gene forbid the normal production of fibrillin which then leads to Marfan syndrome. The gene Fibrillin-1 (FBN1) is located in the chromosome-15 (15q21) of the DNA sequence. A change in your gene will amplify affecting your chromosomes. This will then result on the structural change of a protein because of a change in a DNA sequence. Therefore, this all come together with the cause of the abnormal defect in the function of connective tissue in the human body system.

There is an additional mutation aside from the mutation of Fibrillin-1 gene after further diagnosis. It was discovered that Fibrillin-2, a related protein, may be an additional mutation. “Similarly, when mutations in the gene encoding the microfibrillar adherence to the existing diagnostic criteria gave considerable assurance that the FBN1 gene was the cause of Marfan syndrome. However, additional mutations have been discovered in FBN1 and the gene for a related protein, fibrillin-2 (FBN2).”[ii]

Environmental Factors

Researchers are still seeking for other causes aside from Fibrillin-1 protein mutation in the DNA sequence that may have caused Marfan syndrome. Diet role may play an important factor on the disease. Researchers have questioned the nutritional deficiencies of individuals with Marfan syndrome. It has not been proven but was based on recent studies. “Most researchers say that Marfan syndrome is caused by a mutation in the gene for fibrillin (specifically the fibrillin-1, or FBN-1 gene). However, recent studies show that most people with Marfan syndrome (72%) have not been found to have fibrillin mutations.”[iii] “In 1997, a study of 60 Marfans found that only 28% of the people with the disorder had fibrillin-1 mutations.”[iv]

Figure 1: Nutritional links and Marfan syndrome symptom[v]

Marfan Syndrome Symptom	Nutritional Links
Anxiety disorders, hign adrenaline levels	Magnesium- Anxiety Disorders Low cholesterol- Anxiety Disorders
Blue sclera	Pectus Excavatum
Dislocated lenses	Dislocated lenses
Keratoconus	Magnesium-Keratoconus
Mitral valve prolapse	Magnesium-MVP mitral valve prolapse
Fibromyalgia	Magnesium- Fibromyalgia
Osteopenia and Osteoporosis	Magnesium- Osteoporosis
Rachitic Skeletal Features: Pectus Excavatum, pectus carnitum, bowed limbs, flat feet (pes planus), Hypermobility, acetabuli malformations, scoliosis	Magnesium- Rachitic Skeletal Features Pectus Excavatum Scoliosis Nutrition and Zinc, Zinc, Pectus Excavatum
Attention Deficit Disorder-ADD	Magnesium- ADD
Emphysema in nonsmokers	Magnesium-The similarities to Copper deficiency
Asthma	Magnesium- Asthma
Aorta strength and aortic aneurysms	Magnesium-The similarities to Copper deficiency Magnesium and aorta strength
Allergies	Magnesium- Allergies
Nose Polyps	Salicylates
Scoliosis	Scoliosis causes
Malar hypoplasia (underdeveloped mid face) Micrognathia (small jaws) Higly Arched Palate Marfanoid Habitus	Connective tissue disorder
Stretch marks (striae)	Zinc
Apnea	Magnesium
Muscle weakness	Magnesium
Myopia (nearsightedness)	Magnesium Zinc deficiency symptoms
Various eye disorders- Glaucoma Retinal detachment, Cataracts, Macular Degeneration	Zinc deficiency symptoms and zinc in connective tissue disorders
Calcification of heart valves	Magnesium deficiency Vitamin K deficiency
Nystagmus	Nystagmus
TMJ	TMJ
Nose Bleeds	Nose Bleeds
Neck Pain	Neck Pain
Fibromyaglia	Fibromyaglia diet

Probability Calculation

The probability of having a child carrying the Marfan syndrome lies on a 50% chance. A parent with a normal gene and a partner carrying fibrillin-1 gene mutation will give a 50% chance that this disease will be passed on to their child.