Ricki Lewis

Headlines often trumpet the latest in gene editing, RNA drugs, or gene therapy. The less buzzy, but more classic strategy of providing a nutrient that a genetic glitch blocks, has been quietly making strides against Menkes disease, which impairs copper absorption. November is Menkes disease awareness month.

 

Copper Deficiency

 

Menkes disease results from a mutation in a gene (ATP7A) on the X chromosome, so its affects boys. About 70% inherit the mutation from their mothers, who are carriers. The rest have a new mutation that arises in egg or sperm.

 

The healthy version of the gene encodes a protein that controls enzymes that shuttle copper from food through the lining of the small intestine into the bloodstream, and into the brain, where copper is vital for neural connectivity. The mineral is also essential for hair growth and pigmentation, which is why Menkes is also called kinky hair disease. Boys have sparse, pale, and twisty hairs.

 

Aside from the unusual hair, the child seems healthy until about 3 months. Then symptoms become increasingly noticeable: poor growth, developmental delay, seizures, weak muscles, and low body temperature. Many boys die before their third birthdays.

 

To continue reading, please go to my DNA Science blog at Public Library of Science, where this post first appeared.

The European Medicines Agency has just recommended extending use of an existing drug, nitisinone (Orfadin), to treat alkaptonuria (AKU). AKU holds a special place in the history of genetics as the first "inborn error of metabolism" described. It affects one in 250,000 to one in a million people.

 

The route to impending approval took two decades, illustrating factors that make the quest to discover, develop, and deliver a treatment for a very rare disease so challenging. There's no "Operation Warp Speed" for the rare disease community. Sometimes there aren't even enough participants to carry out a clinical trial that is controlled, relying instead on comparisons to the natural history of a disease, or enrolling one patient at a time in an "N+1" study.

 

I last wrote about AKU in 2014, calling it "black pee disease." I'm happy to report now on the progress in Europe, but won't use that attention-grabbing descriptor, because it minimizes the severity.

A Peculiar Condition and an Astute Physician

 

To continue reading, go to my DNA Science blog at Public Library of Science.

I struggle to stay politically correct when updating my human genetics textbook. “Hemophiliac” became “person with hemophilia” and “victim” vanished several editions ago. In the current incarnation, “mentally retarded” became “intellectually disabled” after colleagues warned that  Read More