Color blindness: the most common genetic disorder

Color blindness is the most common genetic disorder, affecting roughly one in twelve men and one in two hundred women.  Researchers at the University of Washington may have found a cure.

TRANSCRIPT

AS THE MOST COMMON GENETIC DISORDER WORLDWIDE, COLORBLINDNESS AFFECTS ROUGHLY 1 IN 12 MEN AND 1 IN 200 WOMEN, THE OVERWHELMING MAJORITY OF WHOM HAVE TROUBLE PERCEIVING RED AND GREEN.

WHILE THIS MAY BE A MINOR INCONVENIENCE TO SOME, BEING SEVERELY COLORBLIND CAN TAINT SEEMINGLY ORDINARY EXPERIENCES AND CAN PREVENT SOME PEOPLE FROM PURSUING JOBS WHERE COLOR VISION IS CRITICAL.

AFTER A DECADE OF GROUNDWORK, VISIONARY RESEARCHERS AT THE UNIVERSITY OF WASHINGTON MAY HAVE FINALLY CREATED A CURE TO THE COLORBLINDNESS BLUES.

'SCIENCE FRIDAY' PRODUCER LUKE GROSKIN HAS THE STORY.

♪♪

THIS IS SAM.

HE'S A PRETTY SPECIAL MONKEY.

YOU SEE, UNTIL ALL OTHER MALE SQUIRREL MONKEYS, SAM CAN SEE THE COLOR RED, AND HAPPILY PROVES IT IN EXCHANGE FOR A SUGAR PELLET.

IN SQUIRREL MONKEYS, SO ALL THE MALES HAVE COLOR VISION DEFICIENCIES, SO THEY'RE ALL COLORBLIND.

BUT NOT SAM HERE, WHOSE ABILITY TO SMOOSH HIS FACE AGAINST THE PINK DOTS ON A TOUCH SCREEN REPRESENTS A CULMINATION OF COLOR VISION RESEARCH BY JAY AND MAUREEN NEITZ.

MAUREEN IS A, UH, GENETICIST AND GENETIC ENGINEER, AND I'M A NEUROSCIENTIST.

AND SO WE PUT TOGETHER OUR EXPERTISE.

NOT TO BRING MALE SQUIRREL MONKEYS UP TO PAR WITH FEMALES.

OUR WHOLE GOAL WAS EVENTUALLY TO BE ABLE TO DO THIS IN PEOPLE.

COLORBLIND PEOPLE.

MANY OF WHOM MIGHT BE GREEN WITH ENVY WATCHING A MONKEY SEE RED.

THERE ARE A LOT OF MISPERCEPTIONS ABOUT COLORBLINDNESS.

'OH, YOU MUST SEE ONLY IN BLACK AND WHITE.

LIKE A BLACK AND WHITE TELEVISION.'

BUT, UM, ALMOST EVERYBODY WHO'S COLORBLIND IS NOT COMPLETELY COLORBLIND.

99% OF COLORBLIND PEOPLE HAVE THE RED-GREEN VARIETY.

THIS DOESN'T MEAN THEY CAN'T SEE RED OR GREEN, THEY JUST EXPERIENCE RED OR GREEN DIFFERENTLY FROM NORMAL PEOPLE.

AND THIS SMALL GAP IN THE COLOR SPECTRUM CAN TAINT EVEN THE MOST BASIC EXPERIENCES.

A RED PEPPER AND A GREEN PEPPER ALMOST LOOK IDENTICAL.

A GREEN BANANA AND A YELLOW BANANA, AGAIN, THEY'RE VERY, VERY HARD TO TELL.

A SIMILAR FRUSTRATION CAN OCCUR AT THE BUTCHER'S COUNTER.

A COLORBLIND PERSON IS PRETTY LOST AT BEING ABLE TO TELL THE NICE, BRIGHT RED MEATS, UH, USING THEIR COLOR VISION.

AS A MATTER OF FACT, IF YOU -- YOU CAN'T BE A U.S.D.A.

MEAT INSPECTOR, YOU KNOW, UNLESS YOU HAVE PERFECT COLOR VISION.

OTHER JOBS ARE DIFFICULT OR IMPOSSIBLE.

PEOPLE WANNA BE A PILOT OR THEY WANNA BE A NURSE.

A NURSE CANNOT REALLY BE COLORBLIND.

YOU KNOW, THERE'S ALL THOSE PILLS THAT ARE ALL THOSE DIFFERENT COLORS.

IF THE PATIENT'S TURNING BLUE OR IF THEY'RE, YOU KNOW, FLUSHED AND THEY'RE RED.

OR IF YOU'RE A COLORBLIND VIDEOGRAPHER TRYING TO MAKE A VIDEO ABOUT COLOR VISION.

YOU KNOW, IT'S JUST MAKES YOUR LIFE EXTREMELY DIFFICULT.

PREACH ON, DOCTOR NEITZ.

OH, HONEY. LET'S -- LET'S TAKE A VACATION TO VERMONT AND SEE THE BEAUTIFUL AUTUMN COLORS.

YOU KNOW, THE SUNSET.

OH, SWEETHEART, ISN'T IT SO ROMANTIC?

YEAH, COLOR OF THE SKY LOOKS PRETTY MUCH THE SAME.

YOU CAN START TO SEE WHY 1 IN 12 MEN OR 1 IN 200 WOMEN AFFECTED BY THE DISORDER MIGHT BE INTERESTED IN A CURE.

SO IN 1999, WE DECIDED THAT WE WOULD GIVE IT A SHOT AND TRIED TO SEE IF WE COULD DO THE CURE.

EASIER SAID THAN DONE.

COLORBLIND ISN'T AN ILLNESS.

IT'S 100% GENETIC.

RIGHT.

SO THAT, WELL, THAT... [ LAUGHS ]

LET'S BACK UP FOR A SECOND.

AT THE BACK OF YOUR EYE IS YOUR RETINA, AND INSIDE THAT ARE THREE TYPES OF PHOTO RECEPTOR CELLS CALLED CONES.

THERE'S ONE MOST SENSITIVE TO RED, ONE MOST SENSITIVE TO BLUE, AND ONE MOST SENSITIVE TO GREEN.

AND EACH OF THESE CONES AND THEIR CORRESPONDING PIGMENTS ARE ENCODED BY SPECIFIC GENES.

SO HUMANS AND OTHER OLD WORLD PRIMATES HAVE TWO GENES ON THE X CHROMOSOME THAT ENCODE VISUAL PIGMENTS.

ONE ENCODES THE RED CONE PIGMENT AND THE OTHER ONE ENCODES GREEN CONE PIGMENT.

BUT IF YOU'RE COLORBLIND...

ONLY ONE TYPE -- RED OR GREEN -- IS EXPRESSED.

FINDING THAT FAULTY GENE WAS RELATIVELY SIMPLE.

REPLACING THOSE GENES INSIDE THE CONE CELLS WITH THE RIGHT GENES, WELL, THAT'S A BIT TRICKIER.

YOU HAVE TO HAVE SOME WAY OF DELIVERING A GENE TO THE CELLS THAT YOU'RE TRYING TO TREAT AND NOT INTO OTHER CELLS.

FORTUNATELY, NATURE HAS CRAFTED A REALLY POWERFUL METHOD OF FORCING D.N.A. INTO A VERY SPECIFIC CELL -- A VIRUS.

THE VIRUS THAT WE USE IS CALLED ADENO ASSOCIATED VIRUS AND PEOPLE CALL IT A.A.V.

ITS MAIN ADVANTAGE IS THAT YOU DON'T GET AN -- AN IMMUNE RESPONSE AGAINST THE VIRUS.

SO WHILE RESEARCHING HOW TO LOAD THE THERAPEUTIC GENE INTO THE VIRUS, THE NEITZES TRAINED A PAIR OF COLORBLIND MALE SQUIRREL MONKEYS -- SAM AND DALTON -- TO TAKE A COLORBLINDNESS TEST.

EVERY SINGLE MORNING, THE MONKEYS WAKE UP AND BEFORE THEY HAVE BREAKFAST, THEY GO, 'OKAY, IT'S TIME TO HAVE OUR COLOR VISION TESTED.'

AND THE MONKEY IS TRAINED TO TOUCH THE PLACE WHERE THEY SEE, YOU KNOW, THAT COLOR BLOB AND THEN THEY GET A TREAT.

THEY CAN BE MOST EFFICIENT AND GET THE MOST REWARDS IF THEY'RE, YOU KNOW, JUST TOUCH WITH THEIR NOSE AND THEN THEY GET DOWN AND, YOU KNOW, GET THEIR LITTLE TREAT.

AND JUST TO BE THOROUGH...

WE ALSO RAN... [ BUZZER SOUNDING ]

...UNTREATED ANIMALS.

YOU KNOW, OCCASIONALLY, THEY MIGHT JUST BY CHANCE TOUCH THE RIGHT SPOT, BUT ALL OUR TRIALS, YOU KNOW THAT THEY CAN ONLY REALLY GET IT RIGHT ALL THE TIME IF THEY HAVE NORMAL COLOR VISION.

ONCE THE MONKEYS WERE TRAINED AND THE VIRUS WAS READY, SAM AND DALTON UNDERWENT A FAIRLY ELABORATE PROCEDURE.

A VITRORETINAL SURGEON SLIPPED THE NEEDLE UNDERNEATH THE RETINA.

THEN THE FLUID IS INFUSED IN ORDER TO TREAT THE WHOLE ENTIRE BACK OF THE EYE.

IT WASN'T IMMEDIATELY OBVIOUS THAT IT WORKED.

AND WE DIDN'T KNOW HOW LONG IT WAS GONNA TAKE FOR THEM TO CHANGE THEIR BEHAVIOR AFTER THE PIGMENT WAS EXPRESSED ROBUSTLY.

NOW WHEN YOU LOOK BACK AND YOU SEE THE DIFFERENCE BETWEEN THE ANIMALS, IT'S SO DRAMATIC, YOU KNOW.

IT'S AN AMAZING THING, AND IT AMAZED US.

WHILE THE F.D.A. HAS YET TO APPROVE THE PROCEDURE FOR HUMAN TRIALS, RECENTLY, THE NEITZES HAVE DEVELOPED A ONE-SHOT VERSION OF THE CURE.

IT'S LIKE AN EVERYDAY SHOT THAT WOULD TAKE, YOU KNOW, ONE SECOND.

JUST A SHOT RIGHT INTO THE EYE.

AND WHILE GETTING A SHOT IN YOUR EYE SOUNDS TERRIFYING TO SOME, IT'S A SMALL PRICE TO PAY FOR LIVING OUT A DREAM OR GETTING TO SEE A SUNSET IN ALL ITS GLORY.

OR MAYBE JUST NOT LEAVING YOUR HOUSE DRESSED LIKE THIS.

JOINING ME NOW IS 'SCIENCE FRIDAY' VIDEO PRODUCER LUKE GROSKIN.

SO WE GOT A COUPLE OF GLIMPSES OF YOU IN THIS STORY.

YOU'RE COLORBLIND PRODUCING THIS STORY ABOUT COLORBLINDNESS.

THERE ARE SCENES IN THERE WHERE YOU'RE TALKING ABOUT RED PEPPERS, GREEN PEPPERS.

HOW DO YOU FIGURE OUT WHAT'S RED AND GREEN?

UH, A LOT OF TORTURING OF MY FELLOW EMPLOYEES AND, UM, AND MY WIFE.

UH, I REMEMBER THE COUPLE DAYS BEFORE THE VIDEO CAME OUT, I WAS AT 11:00 AT NIGHT BEING LIKE, 'I CAN'T TELL IF THIS IS WORKING.'

AND SHE'S LIKE, 'NO, IT'S NOT WORKING. YOU'RE NOT -- YOU'RE NOT GETTING THE GREEN APPLE GREEN AND THE RED APPLE RED.'

UM, SO A LOT OF FAITH AND TRUST THAT, UH, YOU KNOW, MY COLLEAGUES ARE -- ARE TELLING ME THE RIGHT COLOR.

I MEAN, YOU BASICALLY ARE LIKE SO MANY OTHER PEOPLE WITH THIS.

YOU HAVE COPING MECHANISMS.

YOU GET THROUGH DAILY LIFE.

YOU'RE JUST NOT ENJOYING, AS YOU SAY, THE SUNSETS AND THE COLOR OF THE APPLES AND EVERYTHING ELSE THAT, UH, I MIGHT BE, RIGHT?

BUT, UM, THIS -- THIS RESEARCH, WHERE DO THEY THINK THAT THEY CAN GO WITH THIS?

I MEAN, THIS IS, RIGHT NOW, STILL LITERALLY IN THE MONKEY STAGE.

WELL, THEIR HOPE IS TO START HUMAN TRIALS IN THE NEXT 2 TO 3 YEARS.

UM, AND, IN FACT, VERY RECENTLY JUST IN THE PAST WEEK THEY ANNOUNCED THAT THEY ARE DOING GENETIC THERAPY HUMAN TRIALS TO CURE, UH, RETINAL -- RETINAL DEGENERATIVE DISEASES.

OKAY.

AND, UH, SO THERE'S A LOT OF HOPE THAT THIS IS ACTUALLY GONNA WORK ON PEOPLE.

NOW THIS IDEA AT THE VERY LAST END OF THE STORY, YOU SAID A SHOT IN THE EYE.

OKAY, THAT JUST --

IT'S TERRIFYING. YEAH.

A LOT OF PEOPLE ARE LIKE, 'I WOULD NEVER DO IT.

I WOULD NEVER DO IT.'

BUT I CAN SAY THAT, UM, AS A COLORBLIND VIDEOGRAPHER, I WOULD HAPPILY BE THE FIRST PERSON TO DO THIS.

IT IS A DAILY, YOU KNOW, STRUGGLE TO DEAL WITH THIS.

AND THERE ARE PEOPLE THAT ARE NOT LIVING OUT THEIR DREAMS.

THEY REALLY WANNA BE A PILOT.

THEY REALLY WANNA BE A NURSE.

AND IF IT MEANS JUST GETTING ONE SHOT IN THE EYE, I THINK THAT'S A WORTHWHILE SACRIFICE.

SO EXPLAIN TO ME, UH, WHAT IT FEELS LIKE.

I MEAN, I'VE NEVER EXPERIENCED COLORBLINDNESS.

RIGHT, WE WALK ACROSS THE STREET TO THE FARMERS MARKET HERE, AND YOU -- WE SEE A BUNCH OF COLORED FRUIT -- RED AND GREEN.

WHAT ARE YOU SEEING?

AND HOW DO YOU KNOW THAT IT'S NOT WHAT I'M SEEING, RIGHT?

SO, UH, A GREAT EXAMPLE OF GOING TO A FRUIT MARKET OR SOMETHING LIKE THAT IS WHEN I GO TO BUY BANANAS, I DON'T KNOW IF THEY'RE RIPE OR NOT.

I CAN'T REALLY TELL IF THE GREEN BANANAS ARE RIPE.

AND SO I'LL GO AND I'LL GET A BUNCH OF BANANAS.

AND I'LL BRING IT TO MY WIFE AND SHE'LL BE LIKE, 'NO, HONEY, THOSE ARE BRIGHT YELLOW.

YOU WANNA GET THE GREEN ONES SO THEY DON'T GO BAD ON OUR SHELVES.'

UM, GREEN PEPPERS, RED PEPPERS, MY COLORBLINDNESS IS NOT THAT BAD, BUT A LOT OF PEOPLE THAT I KNOW THAT ARE REALLY, REALLY COLORBLIND, UM, THEY CAN'T TELL THE DIFFERENCE.

THEY -- WHEN THEY SEE THEM, THERE'S A -- THERE'S A SHADE.

THEY'RE A LITTLE BIT DARKER IF THEY'RE RED.

AND SO THAT IS KIND OF THE WAY THAT I AND A LOT OF OTHER PEOPLE THAT ARE COLORBLIND CAN TELL THE DIFFERENCES IN THE COLORS.

IT'S DARKNESS.

SO THERE'S THESE SUBTLE CUES.

BUT DO WE GET THE FULL RANGE OF THE EXPERIENCE?

DO WE MAKE THE MISTAKES?

A LOT OF THE TIME WE DO.

IT'S A PROBLEM.

SO ARE YOU -- DO MOST PEOPLE FIGURE OUT THAT THEY'RE COLORBLIND IN GRADE SCHOOL WHEN THERE'S, YOU KNOW, LITTLE POP-UP BOOKS AND YOU'RE LIKE, 'I'M NOT SEEING THE DIFFERENCE'?

YOU'D BE REALLY, REALLY SURPRISED THAT A LOT OF PEOPLE ACTUALLY GO THROUGH THEIR ENTIRE LIFE NOT REALIZING THEY HAVE A SLIGHT COLORBLINDNESS.

WHEN I SPOKE TO THE NEITZES, THEY SAID TO US THAT, UM, YOU KNOW, THEY'VE TALKED TO PEOPLE THAT WHEN THEY GIVE THEM A COLOR VISION TEST, THESE ARE PEOPLE THAT ARE IN THEIR 30s.

AND THEY TAKE THE TEST AND THEY'RE LIKE, 'OH, YEAH.

YOU HAVE A MILD COLORBLINDNESS.

YOU'RE NOT ACTUALLY SEEING THE WORLD THE WAY THAT OTHER PEOPLE SEE IT.'

UM, IT'S PRETTY COMMON, ACTUALLY.

NOW WEREN'T THERE SOME GLASSES RECENTLY THAT CAME OUT FOR PEOPLE WITH -- THAT THEY COULD TRY AND...

YES.

I'M SURE YOU PROBABLY TRIED IT.

I DID. I DID.

SO EVERY 10 YEARS, ANOTHER COMPANY COMES OUT WITH A PRODUCT THAT THEY SAY CURES COLORBLINDNESS.

IN THIS CASE, THEY'RE NOT SAYING THEY CURE IT.

THEY SAY THEY JUST ALLOW YOU TO, UM, SEE SOME OF THE COLORS THAT YOU WOULDN'T NORMALLY SEE.

I TRIED THEM ON.

I CAN ATTEST TO THE FACT EVEN WITH MY FORM OF MILD COLORBLINDNESS, THEY DID ALLOW ME TO SEE COLORS FOR THE FIRST TIME.

I SAW NAVY. I SAW PURPLE.

I NORMALLY SEE PURPLE AS BLURPLE.

UM, IT'S BLUE PURPLE.

UM, AND IT WAS AMAZING.

IT WAS REALLY, REALLY EYE-OPENING.

THAT SAID, I CAN TELL LOOKING THROUGH THOSE GLASSES, THAT THAT IS NOT HOW A NORMAL COLOR VISIONED PERSON SEES THE WORLD.

BECAUSE WHEN -- BECAUSE IT -- NOT ONLY DOES IT REMOVE CERTAIN WAVELENGTHS OF LIGHT, IT DARKENS EVERYTHING.

AND SO, YOU ARE ACTUALLY EXPERIENCING A -- YOU KNOW, YOU'RE GETTING THE COLORS THAT A NORMAL COLOR VISIONED PERSON WOULD SEE, BUT YOU'RE ALSO LOSING SOME OF THE SPECTRUM AT THE SAME TIME.

MM.

SO IF GIVEN A CHOICE BETWEEN THE GLASSES AND A SINGLE SHOT IN THE EYE, I'D ACTUALLY TAKE THE SINGLE SHOT IN THE EYE.

BECAUSE I ALSO DON'T WANNA HAVE TO WEAR GLASSES ALL THE TIME.

ALL RIGHT, LUKE GROSKIN, THANKS SO MUCH FOR JOINING US.

THANK YOU.