How many chromosomes does a person with tay-sachs have?

Answer 1

It is unknown how many people have Tay-Sachs disease because sometimes the illness is misdiagnosed or not diagnosed in patients. However, it is a very rare disorder that is more common for people with an eastern and central European background.

Answer 2

Tay - Sachs Disease

Tay-Sachs disease (TSD) is a rare but very critical hereditary disease that is passed through both of the parent's gene pool (WebMD [online]). Tay-Sachs usually can first be identified through symptoms of the patient at the age of six months (Health Encyclopedia [online]). The disease is so detrimental because it is a progressive destruction of the nervous system (National Human Genome Research Institute [online]). Tay-Sachs stems off of problems in the lysosomes, the waste processing centers in the cell (Society for Neuroscience [online]). In fact, for children, this destructive process begins in the early stages of pregnancy as a fetus (National Human Genome Research Institute [online]). Tay-Sachs is caused by an excessive amount of a substance known as Ganglioside GM2 build up in tissues and nerve cells in the brain (National Institute of Neurological Disorders and Stroke [online]). This build up occurs because the patient who has this disease lacks an important enzyme known as hexosaminidase A, also know as Hex-A (National Tay-Sachs and Allied Disease Assosiation [online]). Hex-A is in fact a recessive allele to this disease (Naional Geographic Society. Biology: The Dynamics of Life. Tim McGraw-Hill Companies, Inc. 2004. 312). The production of the Hex-A enzyme occurs in Chromosome 15, which is where the defect actually is in tact for Tay-Sachs (U.S National Library of Medicine NIH National Institutes of Health [online]). Every human being has two copies of the gene Hex-A, so when either one, or both of the genes are active it can affectively prevent the build up of the GM2 ganglioside lipid (National Human Genome Research Institute [online]). Although this disease is most commonly found in infants, Late-Onset Tay-Sachs disease does exist, however is a rarity (National Human Genome Research Institute [online]). When affected with Tay-Sachs as an adult it causes neurological and intellectual damage; just as it would as an infant (National Human Genome Research Institute [online]).

Anyone can be a carrier for Tay-Sachs disease, however the risk is truly greater for people of the eastern European Ashkenazi Jewish decent (National Human Genome Research Institute [online]). It is estimated that about one in every twenty seven people of the eastern European Ashkenazi Jewish population carries the Tay-Sachs gene (Health Encyclopedia [online]). Two other populations have also shown greater increase of this disease which include French Canadians, and those of Cajun ancestry (Health Encyclopedia [online]). The only way to receive Tay-Sachs disease is if both parents are a carrier of the disease (National Tay-Sachs and Allied Disease Association [online]). In every pregnancy that both parents are carriers of the disease, there is a one in four, or twenty five percent, chance that the child will inherit Tay-Sachs (National Tay-Sachs and Allied Disease Association [online]). When only one parent is a carrier of Tay-Sachs disease then the child is guaranteed to not inherit it (National Tay-Sachs and Allied Disease Association [online]). However, that leaves a fifty percent chance that the child will become a carrier of Tay-Sachs (National Tay-Sachs and Allied Disease Association [online]). If Tay-Sachs disease does in fact run through your family, or you are of eastern European Ashkenazi Jewish , French Canadian, or those of Cajun ancestry, it is highly recommended that you take a simply blood test (Jackson, Eugene. Diagnostics: Nurse's Preference Library. Intermed Communications Inc. 1983. 132-133). Prenatal testing is offered at the eleventh week of pregnancy using the chorionic villi sampling (National Human Genome Research Institute [online]). If that is passed by, another test is offered at the sixteenth week of pregnancy known as amniocentesis (National Human Genome Research Institute [online]). Testing can obviously also be taken to children who are already born (Jackson, Eugene. Diagnostics: Nurse's Preference Library. Intermed Communications Inc. 1983. 132-133). It is simply another blood test that is taken through the arm, neck, or umbilical cord if just born, and takes merely three minutes (Jackson, Eugene. Diagnostics: Nurse's Preference Library. Intermed Communications Inc. 1983. 132-133).

Those with the disease of Tay-Sachs truly suffer a beating (WebMD [online]). All patients with Tay-Sachs disease have a red spot on the retina of their eye (WebMD [online). At first when the child is born they look completely normal and healthy, but when the child reaches three to six months old the symptoms begin to fall into place (WebMD [online]). Many of those symptoms include decrease in eye contact, twitchy eyes or myoclonic jerks, a difficulty focusing on objects, and even excessive startling by sharp, but not really loud, noises (WebMD [online]). By the age of six to ten months more symptoms appear (WebMD [online]). Limp muscles, otherwise known as hypotonia, decrease in alertness and playness, difficulty sitting, loss of motor skills, a decrease in hearing that will eventually become complete deafness, gradual loss of vision and an abnormal increase in head size (macrocephaly) (WebMD [online]). Finally by the age of ten months and on the final symptoms set in (WebMD [online]). The child does become completely blind and deaf and may become mentally retarded, paralyzed, and not responsive to anything (WebMD [online]). Seizures and difficulty breathing or swallowing are also common (WebMD [online]). Ultimately children with Tay-Sachs disease don't live much after four or five years old (Society for Neuroscience [online]).

Unfortunately there is no cure for Tay-Sachs disease currently (Mayo Clinic [online]). However, there is research and treatment for this horrible disease (Mayo Clinic [online]). Treatment is broken down into three modalities (Mayo Clinic [online]). The first being respiratory care. (Mayo Clinic [online]). Respiratory care is vital; since swallowing is a trouble for people with this disease constant suctioning is extremely important (Mayo Clinic [online]). Without the suctioning pneumonia would quickly set it because of all the mucus leading to the lungs (Mayo Clinic [online]). Also respiratory infections are very common so constant monitoring is necessary (Mayo Clinic [online]). If the patients respiratory rate is high is could possibly mean they have a mucus plug (Mayo Clinic [online]). Also oxygen levels are checked (Mayo Clinic [online]). Nurses use a pulse oximetory to check the amount of oxygen delivered into the lungs (Mayo Clinic [online]). Another problem encountered with this disease is getting the nutrition needed since eating is difficult (Mayo Clinic [online]). Peg tubes and Nasogastric tubes are used for all patients with Tay-Sachs (Mayo Clinic [online]). Nasogastric tubes are temporarily used at the beginning of this diseases journey because they can cause infection (Mayo Clinic [online]). To replace this, a Peg tube is used (Mayo Clinic [online]). A Peg tube is a permanent tube placed in the mid abdomen used primarily as a feeding tube to maintain adequate nutrition (Mayo Clinic [online]). The second treatment process is medication (Mayo Clinic [online]). Since there is no cure for Tay-Sachs, medication is mainly used to limit the amount of seizures (Mayo Clinic [online]). Medication such as Diastat, Dilantin, and Phenobarbital are to control said seizures (Mayo Clinic [online]). Finally the third step is physical therapy (Mayo Clinic [online]). When patients are lying in bed all day not moving, they can become an easy target for becoming paralyzed (Mayo Clinic [online]). Therefore physical therapy is needed (Mayo Clinic [online]). Physical therapy itself is broken down into three segments (Mayo Clinic [online]). Stimulating muscle movement, keeping the joint flexibility in tact, and delaying the joint stiffness (Mayo Clinic [online]). Throughout the entire day the patients are constantly moved, stretched, and given exercises to perform at their best ability (Mayo Clinic [online]). Taking care of a patient with Tay-Sachs disease is a lot of work and requires sacrifice (Mayo Clinic [online]). Even the smallest slip in not watching the patient's vital signs can be detrimental (Mayo Clinic [online]).

Unfortunately, the prognosis for a patient with Tay-Sachs disease is fatal (Mayo Clinic [online]). The outcome for their life expectancy is never over the age of five (Mayo Clinic [online]). This is because Tay-Sachs eats away at your nervous system and cannot be stopped (Mayo Clinic [online]). On September 26, 2009 Craig and Joyln Dewell of Stark County appeared in The Repository for being parents of a daughter with Tay-Sachs disease (CantonRep [online]). Katelyn Dewell, currently about three years old, is affected with this horrible disease (CantonRep [online]). Although this blue-eyed red haired little girl wasn't even thought to have had Tay-Sachs, she is a patient (CantonRep [online]). When asked if they suspected Katelyn of having this disease Craig Dewell, her father, responded with, "Everything looked OK, but then we noticed her eyes twitching. Her pediatrician sent her to an eye doctor, and he saw cherry red spots on her retinas and knew she had a neurological problem." (CantonRep [online]). Obviously the Dewell's are aware of the outcome for Katelyn in which Jolyn says, "She does give us a smiling face when she is happy. You can tell. It's hard, but we wish there were more awareness or help for it. I wish it was something we were all tested for if it takes two people to pass it on to their children." (CantonRep [online]).

Luckily there is research taking place currently for Tay-Sachs disease (National Institute of Neurological Disorders and Stroke [online]). The National Institute of Neurological Disorders and Stroke who are a part of the National Institute of Health are performing many experiments and research across the country (National Institute of Neurological Disorders and Stroke [online]). For the first time in the history of the disease there currently are clinical trials testing the potential of a reduction drug (miglustat) in all three forms of Tay-Sachs (National Institute of Neurological Disorders and Stroke [online]). Also The Cure for Tay-Sachs Foundation has raised roughly one million five hundred and sixty thousand dollars, and also two hundred and eight thousand dollars for research (Tay-Sachs Cure Foundation [online]).

Some interesting facts about Tay-Sachs disease is that it is named after Warren Tay who first described one of the main symptoms of this disease, the red spot on the retina of the eye (Health Encyclopedia [online]). It is also named for Bernard Sachs whose work several years later provided the first description of the cellular changes in the disease (Health Encyclopedia [online]).

Answer 3

The same number as anyone with a normal 2N chromosome complement.

It is a recessive single point mutation and requires 2 copies of the allele to be displayed phenotypically.