Blood Group, I System; Ii

Description

The i and I antigens of the I blood group system are carbohydrate structures carried on glycolipids and glycoproteins and are characterized as straight or branched glycochains composed of repeating N-acetyllactosamine (LacNAc) units, respectively. Conversion of i antigen into an I-active structure requires the activity of the I-branching enzyme, beta-1,6-N-acetylglucosaminyltransferase (GCNT2 ), which adds the decisive GlcNAc-beta-1-6 branch onto the straight poly-LacNAc chains. Expression of the i and I antigens on red blood cells (RBCs) is reciprocal and developmentally regulated. Adult human RBCs predominantly express I antigen, whereas fetal and neonatal RBCs predominantly express i antigen. After birth, I antigen levels increase gradually as i antigen levels fall, with the normal Ii status of adult RBCs reached after about 13 to 20 months. Mutations that specifically affect 1 of the 3 variants produced by the GCNT2 gene cause the rare adult i phenotype, in which adult RBCs are rich in i antigen and contain low levels of I antigen. Mutations that eliminate all 3 GCNT2 variants cause the adult i phenotype with congenital cataract (CTRCT13 ) (review by Yu and Lin, 2011).

Clinical Features

Phenotypes and symptoms related to Blood Group, I System; Ii

  • Cataract
  • Congenital cataract
  • Blood group antigen abnormality

Incidence and onset information

— Currently we don't have prevalence information about this disease (Not enough data available about incidence and published cases.)
No data available about the known clinical features onset.

Alternative names

Blood Group, I System; Ii Is also known as i blood group system, ii blood group system.

Researches and researchers

Currently, we don't have any information about doctors, researches or researchers related to this disease. Please contact us if you would like to appear here.


Mendelian

Accelerate your rare disease diagnosis with us

Learn more

Blood Group, I System; Ii Recommended genes panels

Panel Name, Specifity and genes Tested/covered
Cataract 13 with adult i phenotype (sequence analysis of GCNT2 gene).

By CGC Genetics (Portugal).

GCNT2
Specificity
100 %
Genes
100 %
Cataracts (NGS panel for 41 genes).

By CGC Genetics (Portugal).

BFSP1, BFSP2, VIM, WFS1, FYCO1, PXDN, CHMP4B, P3H2, AGK, SLC16A12, CRYAA, CRYAB, CRYBA1, CRYBA2, CRYBA4, CRYBB1, CRYBB2, CRYBB3, CRYGB, CRYGC , (...)

View the complete list with 21 more genes
Specificity
3 %
Genes
100 %
Congenital Cataracts Sequencing Panel with CNV Detection.

By PreventionGenetics PreventionGenetics (United States).

BFSP1, BFSP2, VIM, FYCO1, PXDN, CHMP4B, P3H2, AGK, SLC16A12, CRYAA, CRYAB, CRYBA1, CRYBA4, CRYBB1, CRYBB2, CRYBB3, CRYGB, CRYGC, CRYGD, CRYGS , (...)

View the complete list with 20 more genes
Specificity
3 %
Genes
100 %
Cataract.

By MGZ Medical Genetics Center (Germany).

BFSP1, BFSP2, SIX6, VIM, WFS1, RAB18, FYCO1, JAM3, TBC1D20, CHMP4B, RAB3GAP1, RAB3GAP2, P3H2, VSX2, COL11A1, COL18A1, COL4A1, COL4A2, SLC16A12, CRYAA , (...)

View the complete list with 44 more genes
Specificity
2 %
Genes
100 %
Eye Diseases - panels.

By MGZ Medical Genetics Center (Germany).

BFSP1, BFSP2, SALL2, BMP4, BMP7, SHH, SIX3, SIX6, FOXL2, SOX2, TACSTD2, ZEB1, TFAP2A, TGFBI, TGIF1, TREX1, TYR, TYRP1, VAX1, VIM , (...)

View the complete list with 146 more genes
Specificity
1 %
Genes
100 %
Cataract panel.

By Centogene AG - the Rare Disease Company (Germany).

BFSP1, BFSP2, VIM, WFS1, UNC45B, FYCO1, CHMP4B, P3H2, VSX2, BCOR, LEMD2, AGK, SLC16A12, SIPA1L3, CRYAA, CRYAB, CRYBA1, CRYBA2, CRYBA4, CRYBB1 , (...)

View the complete list with 25 more genes
Specificity
3 %
Genes
100 %
Cataract, autosomal dominant.

By Centogene AG - the Rare Disease Company (Germany).

GCNT2
Specificity
100 %
Genes
100 %
Cataract Panel.

By CeGaT GmbH (Germany).

BFSP1, BFSP2, VIM, FYCO1, PXDN, CHMP4B, P3H2, BCOR, AGK, SLC16A12, SIPA1L3, CRYAA, CRYAB, CRYBA1, CRYBA4, CRYBB1, CRYBB2, CRYBB3, CRYGA, CRYGB , (...)

View the complete list with 21 more genes
Specificity
3 %
Genes
100 %

We have 8 more panels available in our App

Get the app

Sources and references

You can check the following sources for additional information.

OMIM Rare Disease Symptoms Checker

If you liked this article maybe you will also find interesting the following in-depth articles about other rare diseases, like METHEMOGLOBINEMIA DUE TO DEFICIENCY OF METHEMOGLOBIN REDUCTASE MITOCHONDRIAL MYOPATHY, INFANTILE, TRANSIENT; MMIT EPIDERMOLYSIS BULLOSA SIMPLEX WITH MUSCULAR DYSTROPHY; EBSMD MENTAL RETARDATION, X-LINKED, SYNDROMIC 34; MRXS34 KABUKI SYNDROME 1; KABUK1 SNEDDON SYNDROME

Need help with a diagnosis?

Learn more about how to achieve it with Mendelian


Learn more