Showing posts with label genetics. Show all posts
Showing posts with label genetics. Show all posts

Monday, January 28, 2013

Rampant Diabetes--in the US and in my ancestry

I am not certain how diabetes runs in different families.  I wonder:  does every family have at least one person with Type 2 diabetes?   The statistics are difficult to figure out, especially because organizations such as the American Heart Association keep their numbers by age (child versus adult) rather than by diagnosis (Type 1 versus Type 2). The 2012 American Heart Association Statistical Fact Sheet. for example, says that there were 18.3 million American adults with diagnosed diabetes, 81 million with pre-diabetes, and over seven million adults who are running around undiagnosed.  Nearly 200,000 American children under age 20 had diabetes in 2012.

What we don't know from the AHA figures is how many of those kids had Type 2 because they were heavy and not eating properly, and how many were Type 1, with genetic predispositions and antibodies.

What we also don't know from the AHA statistics is how many of the 18 million grown-ups with diabetes are us Type 1's who are surviving and living normal or near-normal life-spans.  We don't.

So there is no way I can see from these stats to figure out how many of us are living in families with a predisposition toward diabetes.

What I can tell you is this:

I have two antibodies for Type 1.  I was diagnosed as an adult, around age 30, which means I don't fit properly into the AHA categories -- an adult Type 1 doing well.  I am Caucasian and non-Hispanic, so I am from a population that generally is not as predisposed to diabetes.

I can tell you that one of my ancestral lines--specifically my maternal grandmother's mother's line--has family members with Type 1.  My third cousin here in Seattle, a descendant of my grandmother's first cousin, got Type 1 diabetes at about the same age as I.  We have also been told that my grandma had twin cousins with Type 1.  We do not know much beyond that.  The Jewish diaspora, you know...

My maternal grandpa had Type 2 diabetes.

My father's family is a complex story.  Lots of Type 2 diabetes and lots of deaths due to complications of diabetes.  My first cousin Carl, my dad's nephew, has Type 2, and several of his half siblings died of Type 2, including many years ago my cousin Clara, who was morbidly obese.  There were three different mothers, so it's probably a pretty good indication that the diabetes comes from the Bradleys or perhaps my dad's mom's family.  We don't know.

What I do know is that the cards are stacked against these genes of mine.

But from my perspective, it seems that everyone I know has somebody somewhere in their family with diabetes.  It's usually Type 2, but it's there.


Saturday, August 06, 2005

The Genetics of Type 1 Diabetes, by Hsien Hsien Lei

Lei has kindly written this article for the blogathon. She has also written a post on her blog about me, my diabetes related activities and my struggle with diabetes. Lei's blogs include her Genetics and Public Health Blog (where the posts about diabetes are) and her Cotton Pickin' Days personal blog. If you go by her Genetics blog, be sure to check out the article on how humans are genetically similar to pigs!

The Genetics of Type 1 Diabetes
by Hsien Hsein Lei

Type 1 diabetes occurs when the insulin-producing cells of the pancreas are destroyed by the body's own immune system. About 18 regions of the genome, labeled IDDM1 to IDDM18, have been associated with an increase in type 1 diabetes risk.

  • IDDM1 - HLA genes that encode immune response proteins

  • IDDM2 - insulin gene

  • IDDM4 - genes for ZFM1 (zinc finger protein 162), FADD (Fas-associated death protein), and LRP5

  • IDDM5 - SOD2 gene

  • IDDM6 - gene associated with colorectal cancer (DCC), gene that encodes a zinc finger DNA binding domain (ZNF236), and a molecule that opposes apoptosis (bcl-2)

  • IDDM7 - genes for NEUROD1, IGRP

  • IDDM10 - GAD2 gene

  • IDDM11 - genes for ENSA and SEL1L

  • IDDM16 - gene that encodes for immunoglobulin heavy chain

  • IDDM18 - ILB12 gene

  • CTLA4 gene - regulates immune system

  • CD28 gene

  • ICOS gene

Despite these and other candidate genes that have been associated with increased risk of type 1 diabetes, no gene therapy or gene-targeted drugs have been developed thus far. As more genes are discovered and their functions better understood, it will become possible to figure out exactly why some people have type 1 diabetes and to provide them a cure, as well as prevent others from developing it in the first place.

For more detailed information, see The Genetic Landscape of Diabetes, NCBI