Marilee Burdett Leishman's son has GM type 2 Gangliosidoses

Jacob looked this up in his medical books.  It is a genetically inherited disease.

How is GM1 gangliosidosis inherited?

GM1 gangliosidosis is inherited in an autosomal recessive manner.[1][2] Affected individuals inherit 2 mutated copies of the disease-causing gene, one from each parent. Carrier parents (with 1 normal copy and 1 mutated copy) typically are unaffected and do not have any signs or symptoms of the condition. When 2 carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) risk to have the condition, a 50% (1 in 2) risk to be a carrier like each of the parents, and a 25% risk to not have the condition and not be a carrier.

It is important to note that GM1 gangliosidosis is type-specific within families. This means that individuals with a family history of the condition are generally only at increased risk for the specific type of GM1 gangliosidosis in the family.[2     
NIH

This is Marilee's Facebook post:

Hi - I just found out a few days ago that my 5 year old son has Gm1 type two. We thought he had some sort of rare genetic disorder but didn't know what. I am trying to take it all in. Eli was pretty normal until about age 2, except for slight wobbliness and speech delay. Then at age 2 his eyes began to cross and since then he has lost much of his large and fine motor skills, developed kyphosis of the spine and had 3 eye surgeries. He did lose most of the little amount of speech skills he had. He can walk slowly, but tires very quickly, so he now has a walker, which he likes, but he gets frustrated with it, because he gets stuck all the time. And because he falls easily, he wears a helmet to protect his head. He also didn't grow height wise at all from age 4-5. He has thinned out a lot over the past two years, but he still seems to be hungry all the time. He loves food and wants to eat often, and doesn't really know when he's full. Does anyone else have similar experiences? . . . .

. . . . I did notice on here that a ketogenic diet was mentioned. Is that to help with seizures or for the disease? Just wondering if I need to have my son on a special diet. I am overwhelmed by it all....

I have a daughter who is 7 and fine and another boy who has just turned 2. We think he may have it as well, we will hopefully get him tested and know for sure within a few months. The doctor is pretty sure he has it, but I am not ready to deal with that until I know for sure. I have contacted MN to see if we can get HOA testing done. I don't know much about all of that, I know it must be a big ordeal.

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The birth of a child with a recessive condition is often a total surprise to a family, since in most cases, there is no previous family history of the condition. Many autosomal recessive conditions occur this way. It is estimated that all people carry about 20 recessive genes that cause genetic diseases or conditions. It is only when a person has a child with a partner that carries the same recessive gene mutation, that there is a chance of having a child with a recessive disorder.

GM1 gangliosidosis is one of over 50 different lysosomal storage diseases.  It is characterized by the lack of the enzyme, beta-galactisodase.. . . . .  The build up of the GM1 lipid disrupts the normal cell function and causes them to self-destruct; which in turn, leads to the degeneration of the central nervous system and ultimately, death of the affected person.

  Type 2 - Juvenile onset:  this sub-type is characterized by a later onset and typically presents between 1-3 years of age. The children affected have less coarse facial features, hepatosplenomegaly, and skeletal abnormalities.  Life expectancy varies, depending on onset, but many children with Juvenile GM1 gangliosidosis survive until teenage years.        http://gm1gangliosidosis.webs.com/aboutgm1.htm