Later On

A blog written for those whose interests more or less match mine.

The polygamous town facing genetic disaster

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Zaria Gorvett reports for the BBC:

“We are to gird up our loins and fulfil this, just as we would any other duty…” said Brigham Young, who led the Church of Jesus Christ of Latter-day Saints (LDS), or Mormons, back in the mid-19th Century. It was a sweltering summer’s day in Provo City, Utah and as he spoke, high winds swirled dust around him.

The holy task Young was speaking of was, of course, polygyny, where one man takes many wives (also known by the gender neutral term polygamy). He was a passionate believer in the practice, which he announced as the official line of the church a few years earlier. Now he was set to work reassuring his flock that marrying multiple women was the right thing to do.

He liked to lead by example. Though Young began his adult life as a devoted spouse to a single wife, by the time he died his family had swelled to 55 wives and 59 children.

Fast-forward to 1990, a century after polygyny was abandoned, and the upshot was only just beginning to emerge. In an office several hundred miles from where Young gave his speech, a 10-year-old boy was presented to Theodore Tarby, a doctor specialising in rare childhood diseases.

The boy had unusual facial features, including a prominent forehead, low-set ears, widely spaced eyes and a small jaw. He was also severely physically and mentally disabled.

After performing all the usual tests, Tarby was stumped. He had never seen a case like it. Eventually he sent a urine sample to a lab that specialises in detecting rare diseases. They diagnosed “fumarase deficiency”, an inherited disorder of the metabolism. With just 13 cases known to medical science (translating into odds of one in 400 million), it was rare indeed. It looked like a case of plain bad luck.

But there was a twist. It turned out his sister, whom the couple believed was suffering from cerebral palsy, had it too. In fact, together with colleagues from the Barrow Neurological Institute, soon Tarby had diagnosed a total of eight new cases, in children ranging from 20 months to 12 years old.

In every case, the child had the same distinctive facial features, the same delayed development – most couldn’t sit up, let alone walk – and, crucially, they were from the same region on the Arizona-Utah border, known as Short Creek.

Even more intriguingly, this region is polygynous. In this small, isolated community of Fundamentalist Church of Jesus Christ of Latter-Day Saints (FLDS), the likelihood of being born with fumarase deficiency is over a million times above the global average.

“When I moved to Arizona that’s when I realised that my colleagues here were probably the most familiar I’d ever met with this disease,” says Vinodh Narayanan, a neurologist at the Translational Genomics Research Institute, Arizona, who has treated several patients with fumarase deficiency.

What’s going on?

The disease is caused by a hiccup in the process that provides energy to our cells. In particular, it’s caused by low levels of an enzyme – fumarase – that helps to drive it. Since it was perfected billions of years ago, the enzyme has become a staple of every living thing on the planet. It’s so important, today the instructions for making it are remarkably similar across all species, from owls to orchids.

For those who inherit a faulty version, the consequences are tragic. Though our brains account for just 2% of the body’s total weight, they are ravenously hungry – using up around 20% of its energy supply. Consequently, metabolic disorders such a fumarase deficiency are particularly devastating to the organ. “It results in structural abnormalities and a syndrome including seizures and delayed development,” says Narayanan.

Faith Bistline has five cousins with the disease, who she used to look after until she left the FLDS in 2011. “They are completely physically and mentally disabled,” she says. The oldest started learning to walk when he was two years old, but stopped after a long bout of seizures. Now that cousin is in his 30s and not even able to crawl.

In fact, only one of her cousins can walk. “She can also make some vocalisations and sometimes you can understand a little bit of what she’s saying, but I wouldn’t call it speaking,” she says. They all have feeding tubes and need care 24 hours a day.

Fumarase deficiency is rare because it’s recessive – it only develops if a person inherits two faulty copies of the gene, one from each parent. To get to grips with why it’s plaguing Short Creek, first we need to back to the mid-19th Century.

Brigham Young was a busy man. . .

Continue reading.

Written by LeisureGuy

30 July 2017 at 5:14 pm

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