Oculocutaneous Albinism - Genetics from Grandparents

[KB75]

Hi. My son has been diagnosed with Oculocutaneous Albinism, and is now being seen by a genetics counsellor who requires mine and his fathers DNA to test the genes we have, and therefore understand better the genes passed to him to give him this condition. 

I understand enough that me and his father both carry a gene that led to us having a 1:4 chance of having a child with Albinism, and a 1:2 chance they would be a carrier. (Please correct me if i'm wrong!) :-)

We had 2 sons, one has Oculocutaneous Albinism and the other doesn't.

My question is from my father wanting to know how I got the gene? Did it mean both my parents had the  abnormal gene and passed it on...or just one of them? I have 2 full sisters, and my dad has multiple children (my half siblings), none of which show any signs of Albinism. He firstly wondered if I was actually his child or the milkmans ( mum says i'm not ha ha! ), and then corrected himself and asked if he should let all his other kids know they may be a carrier of the gene.

Also, could my son who shows no symptoms be a carrier?

Our next appointment is not until the summer, so i'm really trying to understand the path to why I carry the gene before then........ TIA

 

 

 

 

[StringJunky]

It seems that both your parents probably carry the gene, which is necessary for it to be expressed in their children. If you read this link, it should start you off on enlightening you about it and give you a springboard for looking into it:

https://ghr.nlm.nih.gov/condition/oculocutaneous-albinism#diagnosis

It has an autosomal recessive inheritance pattern, which is where both parents are carriers. The genetic transfer distribution of such a condition amongst in offspring goes something like this picture from my link:

Please be aware that we can't give advice. Save that for when you see your doctor.

Edited January 17, 2019 by StringJunky

[Strange]

1 hour ago, StringJunky said:

It seems that both your parents probably carry the gene, which is necessary for it to be expressed in their children.

As KB75 only seems to be a carrier (and none of her siblings have the disorder) couldn't that come from just one parent? 

If the gene came from her father, presumably any of her full sisters and half-siblings could also be carriers (with a 50:50 chance).

If the gene came from her mother, then only her full sisters could be carriers (again with a 50:50 chance).

Or have I misunderstood how it works?

[StringJunky]

55 minutes ago, Strange said:

As KB75 only seems to be a carrier (and none of her siblings have the disorder) couldn't that come from just one parent? 

If the gene came from her father, presumably any of her full sisters and half-siblings could also be carriers (with a 50:50 chance).

If the gene came from her mother, then only her full sisters could be carriers (again with a 50:50 chance).

Or have I misunderstood how it works?

I think we need @CharonY

Edited January 17, 2019 by StringJunky

[Strange]

2 minutes ago, StringJunky said:

I think we need @CharonY

Send up the bat signal !