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Familiarity, recessivity and germline mosaicism

Familiarity, recessivity and germline mosaicism Summary In man evidence of autosomal recessive disease is usually based on a high sib risk, absence of parent‐child transmission and increased consanguinity. Discrimination from what are sometimes termed multifactorial disorders and their associated environmental effects is usually based on the latter having a lower recurrence risk, an increased recurrence risk after a second affected child and no increase in consanguinity. Another cause of familial disorders with recurrence restricted to sibs which has received little attention is germline mosaicism for a mutation expressed as a dominant. If, for example, an embryonic mutation resulted in half the precursors of the germ cells carrying a mutation with dominant expression, then the proportion of haploid nuclei conveying the mutation, which is the recurrence risk, would be a quarter. If severity precluded reproduction the disorder would tend to be classified as a recessive. While germline mosaicism will rarely be expressed with such a high recurrence risk, the estimation of this risk in rare disorders is difficult due to extreme and unpredictable bias in ascertainment. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Annals of Human Genetics Wiley

Familiarity, recessivity and germline mosaicism

EDWARDS, J. H.
Annals of Human Genetics , Volume 53 (1) – Jan 1, 1989
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References (41)

Publisher
Wiley
Copyright
Copyright © 1989 Wiley Subscription Services, Inc., A Wiley Company
ISSN
0003-4800
eISSN
1469-1809
DOI
10.1111/j.1469-1809.1989.tb01120.x
Publisher site
See Article on Publisher Site

Abstract

Summary In man evidence of autosomal recessive disease is usually based on a high sib risk, absence of parent‐child transmission and increased consanguinity. Discrimination from what are sometimes termed multifactorial disorders and their associated environmental effects is usually based on the latter having a lower recurrence risk, an increased recurrence risk after a second affected child and no increase in consanguinity. Another cause of familial disorders with recurrence restricted to sibs which has received little attention is germline mosaicism for a mutation expressed as a dominant. If, for example, an embryonic mutation resulted in half the precursors of the germ cells carrying a mutation with dominant expression, then the proportion of haploid nuclei conveying the mutation, which is the recurrence risk, would be a quarter. If severity precluded reproduction the disorder would tend to be classified as a recessive. While germline mosaicism will rarely be expressed with such a high recurrence risk, the estimation of this risk in rare disorders is difficult due to extreme and unpredictable bias in ascertainment.

Journal

Annals of Human Genetics – Wiley

Published: Jan 1, 1989

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