Department of Pathology, University of Washington, Seattle, WA 98195, USA.
Genet Med. 2011 Feb;13(2):125-30. doi: 10.1097/GIM.0b013e318202e0f6.
Recurrence of lethal osteogenesis imperfecta in families results from either dominant (parental mosaicism) or recessive inheritance. The proportion of these two mechanisms is not known, and determination of the contribution of each is important to structure genetic counseling for these families.
We measured the recurrence rate of lethal osteogenesis imperfecta after the birth of an affected infant. We determined the rate of parental mosaicism in a subset of families in which we had identified dominant mutations. In 37 families in which two or more affected infants were born, we identified mutations and determined the proportion that resulted from recessive inheritance.
The recurrence rate after the first affected pregnancy was 1.3%. The rate of parental mosaicism in families in which a dominant mutation was identified in a first affected child was 16%. In 37 families with two affected infants, 26 had dominant mutations, seven had recessive mutations, and we failed to find mutations in four. The overall recurrence rate for couples after two or more affected infants was 32%; 27% for families with parental mosaicism, 31% for recessive mutations, and 50% for families with no identified mutation.
In most populations, recurrence of lethal osteogenesis imperfecta usually results from parental mosaicism for dominant mutations, but the carrier frequency of recessive forms of osteogenesis imperfecta will alter that proportion. Mutation identification is an important tool to assess risk and facilitate prenatal or preimplantation diagnosis.
致死性成骨不全症在家族中的复发是由显性(父母镶嵌现象)或隐性遗传引起的。这两种机制的比例尚不清楚,确定每种机制的贡献对于这些家庭的遗传咨询结构非常重要。
我们测量了在一个患病婴儿出生后致死性成骨不全症的复发率。我们在确定了显性突变的一部分家庭中确定了父母镶嵌现象的发生率。在 37 个有两个或更多患病婴儿的家庭中,我们确定了突变,并确定了由隐性遗传引起的突变比例。
首次患病妊娠后的复发率为 1.3%。在第一个患病孩子中发现显性突变的家庭中,父母镶嵌现象的发生率为 16%。在 37 个有两个患病婴儿的家庭中,26 个家庭有显性突变,7 个家庭有隐性突变,4 个家庭未发现突变。两个或更多患病婴儿的夫妇的总体复发率为 32%;父母镶嵌现象的家庭为 27%,隐性突变的家庭为 31%,未发现突变的家庭为 50%。
在大多数人群中,致死性成骨不全症的复发通常是由显性突变的父母镶嵌现象引起的,但成骨不全症隐性形式的携带频率会改变这一比例。突变鉴定是评估风险和促进产前或植入前诊断的重要工具。