Human Genetic Disorder Webquest Bianca Hernandez: Disorder Specialist Courtney Okoyeocha: Parent Erike Arias: Genetic Counselor January 29, 2014 Biology Honors Period 6

Role Disorder Specialist

Disorders The disorders we chose were: Tay-Sachs Disease Colorblindness My role is the Disorder Specialist

What type of disorder is it- gene or chromosomal? Tay-Sachs Disease caused by genetic mutation in the HEXA (hexosaminidase A) gene - karyotype HEXA is critical in the brain and spinal cord enzyme found in lysosomes, which are the structures in cells that break down toxic materials and act as a recycling center recessive gene disorder chromosome 15 mutation reduces/eliminates the activity of the enzyme HEXA, which prevents the enzyme from breaking down GM2 (ganglioside), which begins to accumulate abnormally in cells, builds up toxins, predominantly in nerve cells in the brain and spinal cord. all this leads to the symptoms of Tay-Sachs Disease

Cont. picture of the molecular location of chromosome 15

What are the signs and symptoms of the disorder? 3-6 months muscle weakness an increased startle response Sudden contractions of large muscle when falling asleep 6-10 months lose ability to perform tasks, ex. sitting decreased eye movement/contact & attentiveness After 8-10 months move less & less responsive vision lose & seizures

Cont. 2-4 years old trouble swallowing progress into an unresponsive vegetative state Usually death from pneumonia - inflammation of lungs

What different tests could have been provided to the parent to have found out about the disorder before its birth? Prenatal Testing unborn babies could have been tested for the HEXA Parents could have had a simple blood test to see if they are both carriers, allowing them to refer to a genetic counselor

What other names or abbreviations are used for the disorder? B variant GM2 gangliosidosis GM2 gangliosidosis, type 1 HexA deficiency Hexosaminidase A deficiency TSD

What type of disorder is it- gene or chromosomal? Colorblindness inherited sex-linked recessive disorder 23 chromosome Others include X Chromosome, chromosome 7 chromosome 2, and chromosome % in men are affected Less than ½ of 1% in women affected Mutations in the red and green light-sensitive proteins located on the X Chromosome can cause colorblindness There are 3 categories red-green color vision defects (most common) blue-yellow color vision defects complete absence of color vision – achromatopsia (severely affected, rare)

What are the signs and symptoms of the disorder? Not being able to distinguish different shades of red and green different shades of blue and yellow any colors ex. makes it hard to see the different colors of the rainbow and the color of the sky at sunrise and sunset ex. not being able to tell the difference between the traffic light colors

What different tests could have been provided to the parent to have found out about the disorder before its birth? doctors use a simple eye chart w/ colors implanted in the patterned shapes

Quick Test Ex.1

Cont. Ex.2

Cont. Ex.1 = 2 Ex.2 = 74 some with colorblindness may read 21 or not see anything at all

What other names or abbreviations are used for the disorder? Colorblindness Color Vision Deficiency Color Vision Defects

Role Parent

What kind of lifestyle your child will have with this disorder? My child won’t have a lifestyle if the form is infantile. If my child got the disorder later in, which is rare, my child would live a careful lifestyle.

How long your child will live? If my child got the disorder when he/she was an infant she will live about 4 to 5 years. But if my child got the disorder late around the mid-30s it depends on how severe the symptoms are

If your child with the disorder will be able to have children of his/her own? No my child would not live long enough if gotten as an infant. Yes if my child live long enough.

If child will be affected? There is a 25% chance that the child will be affected.

If you were to have more children, what is the probability that the child will be affected? My child will have a 25% chance of being affected.

What kind of lifestyle your child will have with this disorder? Colorblindness: My child will live a challenging lifestyle. It will a little challenging when learning some things.

How long your child will live? My child will live as long as he/she can. It will not affect his/her life spine.

If your child with the disorder will be able to have children of his/her own? Yes my child can have his/her own child

If child will be affected? My child will have a 50% chance of being affected.

If you were to have more children, what is the probability that the child will be affected? My child will have a 50% chance of being affected if one parent is also.

Sites – Tay-Sachs urces/1http://rarediseases.info.nih.gov/gard/7737/resources/reso urces/1 info/diseases-conditions/neurological-conditions/hic-tay- sachs.aspxhttp://my.clevelandclinic.org/childrens-hospital/health- info/diseases-conditions/neurological-conditions/hic-tay- sachs.aspx ml# ml#

Sites - Colorblindness blindness/inherited-colour-vision-deficiency/ blindness/inherited-colour-vision-deficiency/ blindness-.htmlhttp:// blindness-.html color-vision/basics/symptoms/con http:// color-vision/basics/symptoms/con