LHON

Male/Female Ratios

Relative number of affected men and women

Male Male Male Male Male Male Male Male Male Female


Most people with LHON damaged eyesight are male, but there are some affected women. There are about 9 cases of a male with LHON for every female:

We do not yet know why men are affected more often than women.

Some researchers have suggested that these figures mean that a second gene is involved. This gene would be on the X chromosome, which is one of the sex chromosomes. Other researchers have produced figures which disprove this theory.


Detailed breakdown


In fact the figures are more complicated than the simple picture shown above.

There are about eighteen genetic defects which are found in LHON, but four of these are thought to be 'primary', that is, the main genetic defects responsible for causing eyesight loss. The four defects are known by their position in the DNA chain, so they are called 11778, 3460, 15257 and 14484.


The figures for European populations are :

Male/Female ratio for 11778: 80%

(Over 50% of European LHON patients have the 11778 gene)
male male male male male male male male male male male male male male male male female female female female

Male/Female ratio for 3460: 33-67%

(Around 35% of European LHON patients have the 3460 gene)
male male male male male male male male? male? male? male? male? male? female female female female female female female

Male/Female ratio for 14484: 68%

(Around 20% of European LHON patients have the 14484 gene)
male male male male male male male male male male male male male male female female female female female female

Male/Female ratio for 15257: 75-100%

(Around 15% of European LHON patients have the 15257 gene - often together with 14484)
male male male male male male male male male male male male male male male male? male? male? male? male?


The figures for Asian populations are

Male/Female ratio for 11778: 58 - 90%

(Almost all Asian LHON patients have the 11778 gene. OMIM gives the Male/Female ratio as 58% from one Japanese paper, but some Japanese research puts it at 90%)
male male male male male male male male male male male male female female female female female female female female


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This page last updated 28 March 1999 Copyright © Jim Leeder 1997