N24 Awareness Day 2016: Genetics, the new face of N24 and DSPS.

23 November 2016 at 05:26 | Posted in Body clock, Circadian rhythm, Clock genes, DSPS, N24 | 4 Comments

I got my genes tested this month, and what I found out puts a new face on my understanding of N24 and DSPD.

faces2

The first human genome was sequenced in 2003 and cost 2.7 billion dollars.  Over the years researchers have improved their technique and reduced the cost dramatically.  Recently Veritas Genetics announced it had reached the goal of the under $1000 genome, offering a full genome sequence to anyone for $999.  Still very expensive but quite a drop from 2.7 billion!

Other companies also offer a more limited but still useful form of genomic testing.  One of these is 23andMe which offers testing for $99-$199.  Rather than plunging into the deep end  of whole genome sequencing, I thought I’d go with 23andMe to confirm that I could get useful information with less expense.  I am very impressed with what I was able to find out from 23andMe.

The method of 23andMe is based on analysis of what are called single nucleotide polymorphisms (SNPs).   Most of the human genome is identical from person to person, which is why we are all humans and not horses or banana trees.  SNP analysis focuses on variations in the genome of a particular common type.

The genetic code is a sequence of DNA nucleotides which we label with the letters A,T,G or C.   So part of the code might read like this: …CTGAATGCAGT…  An SNP refers to a situation where one letter of the code differs from person to person.   So while one person may have the sequence CTGAATGCAGT  another may have the sequence CTGAATTCAGT.   Notice the only change is that the letter G in the 7th place has become a T.   Typically one SNP will be more common in the population than the other.  So, for example 90% of the population may have a G, which would be referred to as the major (more common) allele.   The T would be called the minor allele.  (Allele is another word for genetic letters.)

So if you sign up for 23andMe you send them a vial of your spit, and 4-6 weeks later they send you a link to their site where they give you information about a selection of your SNPs and what they mean, as well as some other genetic information.

Most of the information you get from 23andMe, at first glance, seems pretty basic.  They tell you where your ancestors came from and a list of various genetic traits: is your hair likely to be curly, can you taste bitter foods etc.  Interesting but hardly world-shaking in most cases.

But in addition to this pre-analyzed information 23andMe also allows you to download a file containing the raw data: a long list of the actual SNPs and your results.   These you can upload to certain web sites such as Promethease for detailed analysis, or if you know what you are doing and what you are looking for you can look through the raw data yourself.  That’s when the fun begins.

And I knew just what I wanted to look for.

In 2014 Daniel Kripke et al. published an article called, Circadian Polymorphisms in Night Owls, in Bipolars, and in Non-24-Hour Sleep Cycles.  You can get the full text at the link below.

https://synapse.koreamed.org/DOIx.php?id=10.4306/pi.2014.11.4.345

The study identified several SNPs statistically associated with N24 or DSPS.   Not all of the SNPs studied by Kripke et al were tested by 23andMe but three of the most important ones were.

In the case of N24, Kripke et al. were particularly interested in variations in a gene called BHLHE40, or basic helix-loop-helix protein E 40.   The protein produced by this gene plays a major role in the molecular clock.

http://www.uniprot.org/uniprot/O14503

The study found that subjects with N24 were statistically more likely to have one or two C alleles instead of a T at a portion of the genome labelled rs908078, which is part of the regulatory sequence for this gene.   Looking at my 23andMe data I found this line:

rs908078        3       5024771 CT

So, yes indeed I did have one C allele.  It might have been even more impressive if I had two, as some of the N24 subjects did, but one C is still interesting.

But I developed N24 as an adult, following chronotherapy. Before that I had DSPD.  So if there is a genetic predisposition it might be even more likely to show up in genes associated with DSPD.  Kripke et al found two such genes and corresponding SNPS.

The first is a gene called NFIL3 (nuclear factor, interleukin 3 regulated).  It also plays a role in the circadian clock.

https://www.ncbi.nlm.nih.gov/gene/4783

The SNP for NFIL3 is rs2482705, and people with DSPS are more likely to have two G alleles. So looking at my data file I find this line.

rs2482705       9       94182502        GG

So, yes, GG.  I can cross out another letter on my bingo card.

The other gene is RORC (retinoic acid receptor-related orphan receptor C).  This gene has many functions and is not well understood, but one of its roles is also in clock regulation.

http://www.genecards.org/cgi-bin/carddisp.pl?gene=RORC

The associated SNP is designated rs3828057.  People with DSPS are more likely to have a GG allele.  Going back to my data file I search for that string and find this.

rs3828057       1       151780177       CC

You might at first think that was a miss, but remember the structure of DNA.  It consists of two strands linked together in a helix, which run in opposite directions, the sense strand and the antisense strand.   A C in the sense strand matches a G in the antisense strand, and vice versa.  An A matches to a T.  So CC is actually equivalent to a GG in this case.  It simply means one group tested the sense strand and the other the antisense strand.

So we have another hit.

So for the SNPs that were tested  by 23andMe I am 3 for 3 in having the alleles associated with N24 or DSPD.  I don’t want to make too much of this.   These are statistical associations.  It’s entirely possible to have either disorder and not have these genes or to have the genes and not the disorder.  Nonetheless, while I am not yet ready to shout BINGO!,  I find the presence of these genes intriguing.  We aren’t quite ready to trace their function directly to the disorder but that may come in time. The first step in that process is to know what genes are involved. The fact that these genes are ones we do know are intimately involved in regulating the circadian clock is a good omen for our future understanding.

But there is also more on the horizon.  Recall I mentioned 23andMe only tests a limited number of SNPs.   Kripke et al reported a total of 9 SNPs associated with N24.  While rs908078 was the one they focused on the most, the other 8 are also significant.  But 23andMe only tested for rs980078.  They did not test the other 8.  But a whole genome sequencing, if I am ever able to afford that, should give results for the other 8. That’s a lot more letters to put on the bingo card!

I don’t think we are likely to explain N24 or DSPD entirely based on genetics.  Developmental and epigenetic factors almost certainly play a role.  But the more we know about the genetic aspects, the better off we will be. I must also add that genetic studies are not always replicated and it may turn out that all of this is a Will-o’-the-wisp that I will have to retract next year.  But eventually real data will come out.  As one of my favorite fictional characters said, “the truth is out there.”

LivingWithN24 (James Fadden)

This post also appears on the CSD-N web site.  Please join CSD-N to help support research like this.

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N24 Awareness Day 2015 or “How I spent my blogging vacation.”

24 November 2015 at 06:01 | Posted in Circadian rhythm, N24 | 4 Comments

10 years ago my co-blogger Delayed2Sleep started this blog to bring awareness of Delayed Sleep Phase Syndrome. I joined as co-blogger 5 years ago under the name LivingWithN24. We both have continued to blog about issues affecting people with both DSPS and Non-24-Hour Sleep-Wake Cycle Disorder (N24).

I have been very gratified at the number of people online who have told us how this blog has helped them.  For example several people have told me that the post on Charting the Course of N24 helped them make a sleep chart and get a diagnosis.  Others have said that the Melatonin: Less is Sometimes More post has helped them find a dose that finally helps their sleep cycle.

Today is N24 Awareness Day.  It is a day set aside by the online N24 community to help spread awareness of this condition.  This is the third annual N24 Day.

https://n24day.wordpress.com/

In going online at the DSPS blog to write up something for today, I realized I had not posted anything here since last N24 Day.  I had a twinge of guilt, but that soon went away.  I may not have blogged much this year but I have done quite a lot this year concerning N24 and circadian disorders, some of it on my own and some as Vice-President of the Circadian Sleep Disorders Network.

I hope to blog here more in the future but in the meanwhile I thought I’d use this post to update the readers on what I have been doing in the world of N24 and circadian disorders generally.  Some of the readers may already know about this, but many may not and for them I have a lot of useful links and information to share.

Zebra

But first a word about N24 Awareness Day.  The theme for this year is “Think Zebras!”  This comes from a saying taught to doctors “When you hear hoof beats, think horses, not Zebras.”  This means when faced with symptoms look for a common cause not a rare one.  The patient with a cough, fever and muscle aches is more likely to have flu than Q fever.

But this approach leaves people with rare disorders out in the cold.  Those of us with N24 truly are Zebras, and diagnosticians need to keep that in mind.  I have said more about this in my post on the CSD-N site, so rather than repeat myself I will give you a link (and while you are there consider joining.  It is a worthy cause.)

http://www.circadiansleepdisorders.org/info/N24zebras.php

So what else has happened in the world of N24 since the last N24 Awareness Day?  Well a few things…

I was honored this year to be asked to write an article on N24 for the journal Sleep Review.  I should thank Ed Grandi for connecting us, and Sree Roy, the Editor of Sleep Review, for her hard work.  The article is called “What You Need to Know about Non-24”.  It is published online and in digital and paper formats.

http://www.sleepreviewmag.com/2015/05/need-know-non-24/

http://alliedweb.s3.amazonaws.com/sleeprev/diged/201508/html5/index.html

I have been very gratified by the reception of the article by both patients and health professionals.   A friend recently told me it turned up in the waiting room of her sleep clinic.  So word is getting around about N24.

(This was my second formal article on N24.  The first, which I don’t think I have linked to on this blog, is a report on N24 for the National Organization of Rare Disorders, which I co-authored with Dr. Katherine Sharkey a couple of years ago: http://rarediseases.org/rare-diseases/non-24-hour-sleep-wake-disorder/)

Another high point of the year was participating in an online course offered by Coursera called Circadian Clocks – How Rhythms Structure Life.   It was taught by two eminent circadian researchers, Martha Merrow and Til Roenneberg of Ludwig-Maximilians-Universität München. I am not sure if the course will be offered again, but if you have a serious interest in circadian rhythms I highly recommend it.

https://www.coursera.org/course/circaclock

Finally, another major event this year was the publication of new guidelines for the treatment of circadian disorders by the American Academy of Sleep Medicine.

http://www.aasmnet.org/practiceparameters.aspx?cid=116

A preliminary version of the guidelines was released earlier and interested parties were asked to comment.  The deadline for comments was very tight.  CSD-N submitted comments on the guidelines.  In addition to helping compose the CSD-N comments I also submitted additional comments of my own which we did not have time to incorporate into the official CSD-N comments.

The most important aspect of the AASM guidelines — both their strength and weakness — is that they are based on a strict interpretation of the concept of evidence-based medicine.  According to this approach only treatments which have been subjected to controlled clinical trials are given a recommendation.  And clinical trials have to meet a number of strict criteria to be counted.

This is often a useful constraint.  It avoids the recommendation of treatments which are ineffective.  It is particularly useful in the case of common disorders where clinical trials can be organized. (To give an example from personal experience, I recently suffered a bout of diverticulitis.  Antibiotics are often prescribed for this condition but at least 5 controlled trials have demonstrated that they make absolutely no difference in outcome.)

However, in the case of rare disorders such as N24, this restriction can be both a blessing and a curse.  Given the rarity of sighted N24s there are very few clinical trials, and those that have been done did not meet the criteria of the AASM.  Thus the guidelines give “no recommendation” for any treatment of sighted N24.   For N24 in the blind, melatonin agonists are given a “weak for” recommendation.

The good side of this is it amply demonstrates the urgent need for more studies of treatments for N24, particularly in sighted patients.  It is intolerable that there is no validated treatment for such a devastating disorder.

The bad side of this approach is that it discounts evidence such as case reports of the efficacy (albeit partial and with limitations) of treatments for sighted N24, in particular light/dark therapy or combinations of light/dark therapy with melatonin.  In the absence of clinical trials for a rare disorder, case reports may be better than no evidence at all.  Nevertheless it is true that in the absence of controlled trials we don’t know how effective such treatments are for sighted N24s as a whole. This is an issue I may discuss more in the future.

So that has been my past year of involvement with N24 awareness.  In summary, there is more attention being paid to this condition.  But we still have a long way to go.  We need better understanding of the underlying biology of N24 — which is still poorly understood — and we need validated treatments.

— LivingWithN24 (James Fadden)

62. Psychiatric misdiagnosis of N24

31 March 2011 at 05:27 | Posted in Circadian rhythm, Melatonin, N24 | 21 Comments
Tags: , , , , ,

I’ve been reading an interesting article on a case of psychiatric misdiagnosis of N24 in a 14-year old.  This poor kid was given a long list of severe and pejorative psychiatric diagnoses, all of which resolved completely when his circadian rhythms were normalized with melatonin treatment.  He had dropped out of school for two years and was sent to a child psychiatric hospital.  After treatment was able to return to school and do well.  This case shows how easily N24 (and DSPS) can be misdiagnosed.  The boy was also lucky he responded to melatonin as many N24s do not.

Here is the description of his case before proper diagnosis and treatment:

During the 4 years before referral,
the patient suffered from major functioning difficulties
including conflicts with teachers, parents, and peers. He
was described by a licensed child psychologist as being
extremely introverted with severe narcissistic traits, poverty
of thought, and disturbed thinking, including
thoughts with persecutory content and self-destruction
that led to a paralyzing anxiety, anhedonia, social isolation,
and withdrawal. Assessment of learning disabilities
revealed difficulties with written language and poor
visual and auditory memory. Assessment also revealed
above-average performances in verbal comprehension
and abstract reasoning.

Two years before referral, the patient dropped out of
school and was sent to an inpatient child psychiatry center.
Three months of psychiatric evaluation yielded diagnoses
of atypical depressive disorder with possible
schizotypal personality disorder. He was described as
sleepy and passive, especially in the mornings.

The patient was diagnosed using actigraphy (a wrist monitor that measures movement) and with 24 hour sampling of melatonin and temperature rhythms.  This is his actigraphy chart showing the classic N24 pattern in which the waking period shifts later each day.  The black peaks on the chart show movement, indicating the time of day or night during which he was awake.

Treatment with 5mg of melatonin (a large dose) at 8pm resulted in a normalization of his circadian rhythms within a month.

Here is how he was described after proper diagnosis and treatment:

The patient returned to school after a 1 years absence
and succeeded in filling the gaps of missing studies. At the
end of the first semester, his school report showed excellent
results. His parents also reported an improvement in
the patients relationship with his family and peers.
In a psychiatric evaluation by licensed psychiatrists,
none of the previously described severe diagnoses were
present, and the boy showed no evidence of psychopathology,
as was previously thought.

One wonders how many adolescents — and adults — are misdiagnosed with various severe psychiatric disorders simply because no one looked for a circadian rhythm sleep disorder.   The case was reported by Yaron Dagan and Liat Ayalon two of the best researchers on the clinical manifestations of N24 [1].

1.  Dagan Y, Ayalon L. Case study: psychiatric misdiagnosis of non-24-hours sleep-wake schedule disorder resolved by melatonin. J Am Acad Child Adolesc Psychiatry. 2005 Dec;44(12):1271-5.

–Posted by LivingWithN24 (James Fadden)

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Next post:  63. Sleep research in the USA

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