Benign familial hyperphosphatasaemia as a cause of unexplained increase in plasma alkaline phosphatase activity.
OBJECTIVE
To consider a possible genetic origin for the persistent unexplained increase in plasma alkaline phosphatase (ALP) in five non-related patients referred over an 18 month period.


METHODS
Plasma ALP isoenzyme activities were measured in patients and their first degree relatives.


RESULTS
In each patient there was a noticeable increase in intestinal plasma ALP, either alone or accompanied by an increase in bone or liver ALP. Family studies showed an unexpected increase in plasma ALP and similar isoenzyme changes in first degree relatives. The findings were consistent with autosomal dominant inheritance.


CONCLUSIONS
Inherited raised plasma ALP activity is a reasonably common cause of persistent unexplained hyperphosphatasaemia which deserves wider recognition.
Rosalki
S B
SB
Department of Chemical Pathology and Human Metabolism, Royal Free Hospital and School of Medicine, London.
Foo
A Y
AY
Dooley
J S
JS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood*; D001842:Bone and Bones / Q000201:enzymology; D005190:Family; D005260:Female; D006801:Humans; D007422:Intestines / Q000201:enzymology; D007527:Isoenzymes / Q000097:blood; D008099:Liver / Q000201:enzymology; D008297:Male; D008875:Middle Aged
D007527:Isoenzymes; D000469:Alkaline Phosphatase