case 8.. easy one

[md90]

A 5-month-old girl is brought to her pediatrician by her parents, both of whom are Jewish. Although the baby girl was developing normally for the first 4 months of her life, she can no longer roll over by herself. In addition, while she often smiled at 3 months of age, she no longer does so. Funduscopic examination reveals a "cherry-red" spot on her macula.

1. What is the most likely diagnosis?
2. What is the biochemical defect in the this condition, and what is the enzyme used for or its' purpose?
3. How is this gene responsible for this condition inherited?
4. Name the other disease from the same group but inherited in a different way, and name that inheritance.
5. What other conditions present with similar findings on physical examination?
6. What other disease in the same group also have a higher prevalence among the Ashkenazi Jews?

[MDiva]

Well, I'll take the first one. Tay-Sachs disease.

[Unswer]

1. What is the most likely diagnosis?
2. What is the biochemical defect in the this condition, and what is the enzyme used for or its' purpose?
3. How is this gene responsible for this condition inherited?
4. Name the other disease from the same group but inherited in a different way, and name that inheritance.
5. What other conditions present with similar findings on physical examination?
6. What other disease in the same group also have a higher prevalence among the Ashkenazi Jews?

1-taysah
3-resecive
5-nimanpic

[md90]

1-taysah
3-resecive
5-nimanpic

Good.. MDiva and unswer... except need to be specific whether is autosomal or x-linked recessive..(look below)

1. Tay-Sach's (one of the sphingolipidoses)
2. deficiency of hexosaminidase A which is present in the lysosomes of the CNS cells and helps to degrade the GM2 ganglioside (accumulation leads to progressive neurodegeneration)
3. Autosomal recessive
4. Fabry's is X-linked (only sphingolipidose)
5. Niemann's Pick
6. Gaucher's disease--B-glucocerebrosidase deficiency

[IMG SURVIVOR]

what is this GM2 ganglioside?

do we need that?

[md90]

what is this GM2 ganglioside?

do we need that?

from what I understand... GM2 ganglioside is a lipid, and it helps in the regulation of making the dendrites in the pyrimidal neurons of the cortex; once these dendrites have matured, the GM2 ganglioside are decreased and sent to the lysosomes to be degraded by the hexosaminidase A enzyme. But if there is a deficiency or no enzyme, then it can not be degraded, and it accumulates leading to a progressive neurodegeneration; Children will first become deaf and blind, then paralysis will set in... usually will die by age 2 or 3 years.