Which of the following is NOT considered an autosomal dominant condition?

Tay-Sachs disease is the condition that is not considered autosomal dominant. Instead, it is an autosomal recessive disorder caused by a mutation in the HEXA gene, which leads to a deficiency of the enzyme hexosaminidase A. This enzyme deficiency results in the accumulation of GM2 gangliosides in nerve cells, leading to progressive neurodegeneration.

In contrast, Von Hippel Lindau disease, Neurofibromatosis type 1, and Marfan's syndrome are all classic examples of autosomal dominant conditions. In autosomal dominant disorders, only one copy of the mutated gene from an affected parent is sufficient to cause the clinical manifestations of the disease in offspring. This means that affected individuals have a 50% chance of passing the trait to their children with each pregnancy.

In summary, recognition that Tay-Sachs disease is autosomal recessive is key, while the other listed options represent disorders that follow an autosomal dominant inheritance pattern. Understanding these inheritance patterns is critical for both genetic counseling and clinical management.