Dr Fred Kavalier: A Question of Health

Can you give us any information on Androgen Insensitivity Syndrome (AIS)? Our daughter didn't start her periods and has just been given this diagnosis. We know that it used to be called Testicular Feminization Syndrome and that it involves a girl having XY chromosomes and no womb.

Can you give us any information on Androgen Insensitivity Syndrome (AIS)? Our daughter didn't start her periods and has just been given this diagnosis. We know that it used to be called Testicular Feminization Syndrome and that it involves a girl having XY chromosomes and no womb.

AIS is a rare condition that is caused by a faulty gene on the X chromosome. The effect is that testosterone, the male hormone, cannot exert its masculinising effect. This means that a baby who is genetically a boy (with XY sex chromosomes), is born with all the external physical features of a girl. The condition is often not diagnosed until puberty, when a girl doesn't start her periods. Girls with AIS don't have periods because they don't have a uterus or ovaries. They do, however, have testicles that are hidden either in the tissues of the groin or inside the abdomen, and these will probably have to be removed surgically. Girls with AIS and their families need support and information. The AIS Support Group is at: AISSG UK, PO Box 269, Banbury, Oxon, OX15 6YT. Helpline 01295-670140; their website is at: www.medhelp.org/ www/ais/

Medicines like paracetamol give a dosage of 'not more than two at a time and not more than eight in a day'. How can the same dose be right for both an 8-stone woman and a 19-stone man? I am the 19-stone man, and I take codydramol for osteoarthritis in my knees. I take two in the morning, three after lunch and two more in the evening. Should I be more careful?

Body size is important in calculating drug doses, although it is more important in small children than in adults. For adults, recommendations, such as "two tablets four times a day", are for an average size person. They tend to err on the side of caution, to minimise the risks of side effects and overdosage. Codydramol contains paracetamol, which can be very toxic to the liver if you take too much. I don't think you will get into trouble by taking three at a time, as long as the total daily dose is fewer than eight. Another suggestion is to lose a few stone. Being overweight is probably one of the reasons why your knees are arthritic.

E-mail your questions to health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions