G6S Point Mutation in Nubian Goats
a neurodegenerative genetic disease
What is G6S?
G6S is the name of a specific gene found in Nubian goats and their hybrids. It is responsible for the production of N-acetylglucosamine-6-sulfatase (G6S), which is an enzyme that is involved in the catabolism of heparin sulfate. There is a single nucleotide polymorphism (SNP) that results in an inability to produce G6S, resulting in an accumulation of heparin sulfate in the affected animal's lysosomes, which in turn affects other enzymatic activity within the lysosomes. (pictured: SGCH Saada Bellfry's Lady Vampress, a nationally-ranked goat who may have been a carrier)
How is G6S inherited?
Progression of an animal (Running River Diversion) with G6S affected status
In hindsight, symptoms may be obvious, but her posture is not unusual for a newborn triplet. She is a little small and hunched, but again it is not unusual for one animal from a set of triplets to be small, and newborns are often hunched to preserve heat.
Still a fairly normal-looking young goat. She's a little narrow overall and a little pinched in the barrel, but not at all 'diseased' in appearance. She comes from a very dairy line, and it is normal for such animals to be rather lanky especially when young.
Here we can see some of the effects of G6S. She's hunched and severely camped under, she is lacking in condition and muscle tone, and her eyes are weepy. These are very general symptoms of an unwell goat, which is part of what has made G6S go unnoticed for so long. This animal died a year after this picture was taken.
why should we care about G6S?
Symptoms of G6S deficiency
How prevalent is this disease? Do we really need to worry about it?
Can we eliminate it?
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Science (New York, N.Y.) vol. 199 (4324) p. 79-81
Clavijo, Alfonso; Sun, Feng; Sneed, Loyd(2010)
Journal of Veterinary Diagnostic Investigationvol. 22 (4) p. 622-627
2 J VET Diagn Invest 1998 10: 181 Margaret Z. Jones Heidi M. Hoard, Jeffrey R. Leipprandt, Kevin T. Cavanagh, Nancy K. Truscott, Beverly A. L. Levene, Karen H. Friderici and Determination of Genotypic Frequency of Caprine Mucopolysaccharidosis IIID