Memory Project: My Green Spectacle Case

 

I recently chanced upon this spectacle case when rummaging through a bottom drawer filled with miscellaneous junk. The sight of it got me thinking about the history of my accursed affliction.

At the beginning of 1958 Alan was enrolled at Chaplin High School and entered Form 1. Towards the end of Standard 5 he had already begun to have difficulty seeing what was written on the blackboard, and high school proved a challenge. The optician he was taken to was unable to correct his myopia with glasses, and he was referred to a specialist in Bulawayo. He was diagnosed with a hereditary condition affecting the retina and was told that there was no treatment currently available.

If the condition was hereditary, both my parents probably thought, it couldn’t be from their side of the family, there being no record of it, as far as they knew.  They would have been unaware of Mendel’s experiments with peas and his rules governing the inheritance of traits. They would have known nothing about recessive genes and the way a trait can skip many generations until the carriers of a faulty code meet and mate.

At the start of 1963 I also moved up to Chaplin and went into Form 1. It was in the maths class that I discovered my eyesight had deteriorated, leaving me unable to follow the explanation of algebraic equations on the board. Thus began the relentless onset of Stargardt disease, an autosomal recessive gene disorder for which there is still no treatment.

According to Mendelian rules my parents, as unwitting carriers of the dodgy gene, had a 1 in 4 chance of producing offspring with the disorder. For their first child to be afflicted was unfortunate, for the second to get it was 1 in 16 bad luck, but for the third to have it was a 1 in 64 blow that could lead one to suspect that a malevolent force was deliberately victimizing the Martin family. Jean’s turn came four years later when we were back in Fish Hoek.

Stargardt disease has been a handicap and then a disability. For the first 30 years, while it made life difficult and put me at a disadvantage, I was able to lead a fairly normal life. Then, in the last 25 years it has disabled me in two important ways. Not being able to read or drive have made it almost impossible to work and earn a living. I am now heavily dependent on my wife and, to a lesser extent, our two children.

I feel very little pity for myself, and have never asked stupid questions like, Why me? As a rational atheist it would be pointless cursing God, or Providence, or Fate.  Nor do I believe that having to cope with this lifelong affliction has made me a stronger character. Stoicism and an ironical cynicism have helped, but I regard myself with a certain amount of self-loathing, and feel that I have probably got what I deserve.

The spectacle case was originally one of my mother’s. A section of the material covering it is torn and reveals the aluminium beneath it.  The glasses did little to correct my myopia, and being excessively self-conscious I never wore them. I have not yet decided whether to throw the case in the dustbin, or to preserve it as an interesting artefact of historical interest, and drop it back in the drawer along with the other now useless relics from the past.

There can be no doubt that my parents were blameless in transmitting the dodgy gene to all three of their offspring. However, in my case, I stand guilty of having risked the possibility of subjecting my children to an incurable hereditary disorder. At the time, I knew there was a chance they could inherit my disability, yet I went ahead and committed premeditated reproduction, not once but twice.

That was some 40 years ago. Now, with a better understanding of recessive gene disorders, and having experienced the effect of Stargardt disease, I would urge anyone who knows they might be a carrier of the faulty ABCA4 gene to take advantage of modern genetic screening before condemning a child to the kind of crap I, and my siblings, have had to contend with.

 

 

 

I asked perplexity.ai to explain how Stargardt could be passed to all three of a couple’s children, and this is what it told me:

 

Stargardt disease, an autosomal recessive disorder, requires both parents to pass a mutated ABCA4 gene to their offspring. While the typical inheritance pattern predicts a 25% chance per child, all three offspring inheriting the condition is statistically unlikely but biologically possible. Here's how this can occur:

Genetic Mechanism

1. Carrier Parents: Each parent has one functional ABCA4 gene and one mutated copy. Since carriers don’t exhibit symptoms29, they may be unaware of their genetic status.
2. Inheritance Odds:
• 25% chance a child inherits two mutated copies (one from each parent) and develops Stargardt disease.
• 50% chance the child becomes a carrier (one mutated copy).
• 25% chance the child inherits no mutated copies24.
3. Statistical Probability: While each pregnancy is independent, the probability of all three children inheriting two mutated alleles is 0.253=1.56%0.253=1.56%4. Though rare, this outcome is possible due to random assortment of genes during reproduction.

Factors Influencing Outcomes

• Allele Severity: Some ABCA4 variants are "mild" and may not cause childhood-onset symptoms, complicating predictions about when or if symptoms manifest.
• Incomplete Penetrance: Rare cases may involve environmental or genetic modifiers affecting disease expression, though this is less common in Stargardt disease.

Real-World Context

Most autosomal recessive disorders like cystic fibrosis or sickle cell anemia follow similar inheritance patterns. Genetic testing can identify carrier status, but without screening, families might only discover their risk after having an affected child67. For Stargardt disease, the estimated risk for offspring of carriers ranges from 1.6% to 3.1%, depending on allele severity combinations8.

In summary, while unlikely, the inheritance of Stargardt disease in all three children of carrier parents reflects the probabilistic nature of genetic transmission rather than a deviation from Mendelian principles.

 

People also ask

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