In the may issue, this column featured disorders that occur only in men, but are always inherited through their mothers. They included hemophilia, red-green colour blindness and the two forms of muscular dystrophy. In this continuing series, we bring you more information on other hereditary disorders that only occur in men.

 Colour Blindness

Do you know you could be colour blind and don’t have an idea that you do? It means that, for instance, you can’t differentiate between red, green and yellow – they all look grey to you! That’s the tragedy of colour blindness. However, you are not alone. About eight per cent of all men are colour-blind  – meaning millions are culprits without realising it. And as a man you are ten times more vulnerable than a woman, hence colour blindness is almost a male affliction. Moreover, nothing can be done about this hereditary defect in the eye structure.

There are various forms of colour blindness, but more than half of all cases are ‘red-green colour blindness.’ This is one of the types linked with sexual inheritance. In this condition, all three normal pigment responses occur in the eye but there is difficulty in telling red, green and yellow apart – all are likely to appear greyish. This can occur in various degrees, ranging from slight greying from a distance, to identical response to vivid colours close at hand.

A colour-blind person will not normally realise for himself that he is colour-blind, but special tests can reveal his defect. Charts covered in coloured dots are used. These reveal a pattern or number to a person seeing them with normal vision, but no pattern or a different one to those with colour defects.

 Hernia

Another condition that prefers men is the hernia, where a body organ protrudes through the wall of the body cavity. This happens most often in the abdomen – part of the stomach or intestine is pushed through the abdominal wall. Hernias occur where the cavity wall is weak, either because of a natural gap where a blood vessel or digestive tissue passes, or because of scar tissue.

You can either be born with a hernia or acquire it along the way. Inguinal hernias are by far the most common. In men, the inguinal canal is the pathway down which the testes descend just before birth. In later life it contains the spermatic cord and blood vessels. In an inguinal hernia, part of the intestine protrudes down this canal into the scrotum.

Congenital hernias are caused by the failure of some tubes to close properly during foetal development. The intestine is either displaced at birth or easily becomes so.

Acquired hernias are caused by any form of straining or exertion that increases pressure in the abdomen and forces it through a weak spot in the abdominal wall, such as physical work, straining at the bowels or violent coughing. Strain and exertion equally act as predisposing factors, that is, they weaken the abdominal wall, as does any large, sudden gain or loss in weight. Because men do heavy manual work, they are prone to the hernia.

Symptoms…

These depend on the type and condition of the hernia, the size and tightness of the opening, and the amount of the organ involved. The onset of the hernia may be gradual, with the symptoms increasing till they become noticeable; or sudden (perhaps while lifting a heavy weight), in which case the person is often aware of something having given way, perhaps with varying degrees of pain.

In general, there is a feeling of weakness and pressure in the area, an occasional pain or continual ache: and a gurgling feeling in the organ under strain. A swelling may be present all the time or may appear only under pressure. Swellings that are continually present may increase in size.

Digestion is disrupted, usually causing constipation. Strangulated hernias produce special acute symptoms. When the blood supply is cut off, the protruding tissue dies and swells thus increasing the pressure in the opening. The hernia becomes inflamed and acutely painful and the skin over the area may redden. The dead tissue in the hernia quickly becomes gangrenous, often within five or six hours, and this in turn causes peritonitis-inflammation of the abdominal lining and its contents. If untreated, death occurs within a few days.

Hernias are often held in place by a truss – a belt with a pad that is fitted over the hernia. But as long as the hernia exists, the risk of future strangulation remains. Most hernias are therefore treated surgically. Any damaged tissue is removed, the protruding organ replaced in the abdomen, and the opening stitched up again. Strangulated hernias require immediate operation.

Published in June 2012