IDC-10 Code = E76.22
Enzyme Commission Number = EC# 3.1.6.14
Genomic coordinate (human 12:64,713,449 GNS).
Cytoband (human 12q14.3 GNS).
Intraband %= 43.8% GNS
OMIM’ genes @ 12q14.3 = 32 genes.
ClinVar = 846 GNS variants reported.
Hyperbolic Umbilic Chromosome-12 is 1,200 genes.
Chromosome-12 Cytobands: WG2B2GC_CBG5B2G6
| 白灰₂黑₂灰縊_縊黑灰₅黑₂灰₆ |
Here I 🎁 present: “Sanfilippo Type-D Syndrome”, Victor McKusick, Mendelian Inheritance in Man’, 1966.
INTRODUCTION.
Sanfilippo Type-D Syndrome is caused by deficiency of the enzyme N-acetylglucosamine-6-sulfatase (GNS), one of four enzymes whose loss causes the four Sanfilippo subtypes (A–D). All four impair breakdown of the glycosaminoglycan heparan sulfate.
Without this enzyme, heparan sulfate accumulates in lysosomes, especially in neurons.
Over time this leads to progressive neurodegeneration, which clinically presents as developmental regression, behavioral changes, sleep disturbance, and loss of motor/cognitive function — the hallmark of Sanfilippo syndrome.
The red-to-blue fold surface is a stylized way of showing the “tipping point” — normal function (red) collapsing abruptly toward accumulation/degeneration (blue) once enzyme activity drops below a critical threshold, rather than a smooth linear decline.
