Thromb Haemost 1994; 72(04): 534-539
DOI: 10.1055/s-0038-1648909
Original Article
Schattauer GmbH Stuttgart

Molecular Basis of Antithrombin Type I Deficiency: The First Large In-frame Deletion and Two Novel Mutations in Exon 6

J Emmerich
1   INSERM CJF 91-01, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris V and Centre Claude Bernard de recherche sur les maladies vasculaires, Hôpital Broussais, Paris, France
,
G Chadeuf
1   INSERM CJF 91-01, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris V and Centre Claude Bernard de recherche sur les maladies vasculaires, Hôpital Broussais, Paris, France
,
M Alhenc-Gelas
1   INSERM CJF 91-01, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris V and Centre Claude Bernard de recherche sur les maladies vasculaires, Hôpital Broussais, Paris, France
,
M Gouault-Heilman
2   Laboratoire d’Hématologie, Hôpital Henri Mondor, Créteil, France
,
P Toulon
3   Laboratoire d’Heéatologie, Hôpital Cochin, Paris, France
,
J N Fiessinger
1   INSERM CJF 91-01, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris V and Centre Claude Bernard de recherche sur les maladies vasculaires, Hôpital Broussais, Paris, France
,
M Aiach
1   INSERM CJF 91-01, UFR des Sciences Pharmaceutiques et Biologiques, Université Paris V and Centre Claude Bernard de recherche sur les maladies vasculaires, Hôpital Broussais, Paris, France
› Author Affiliations
Further Information

Publication History

Received 22 April 1994

Accepted after revision 27 June 1994

Publication Date:
06 July 2018 (online)

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Summary

We report three novel mutations accounting for cases of inherited type I antithrombin (AT) deficiency. Using the polymerase chain reaction (PCR) and direct sequencing of the coding sequences of the AT gene, we found one mutation in exon 4 and two in exon 6. A deletion of 105 bp causing an in-frame deletion of 35 amino acids between Tyr 240 and Gly 276 was found in exon 4. In a second kindred, deletion of two adenines in codon 412-413 introduced a frameshift and a stop codon at position 431. The last mutation was an insertion of ACCG in codon 387, generating a frameshift with a stop codon located at the normal position.

The finding of a sequence repeat of nine residues located at the 5’and 3’ ends of the deleted fragment might explain the 105 bp deletion by slippage and mispairing at the replication fork during DNA synthesis. The second mutation is the fourth described within a region of six amino acids (between Phe 408 and Arg 413), which seems to be a cluster of mutations. In this case, the presence of a double repeat sequence - TTCCT and AACA - flanking this region could be particularly favorable for slipped mispairing.

These results confirm that human gene mutations are not random events but are strongly influenced by DNA flanking sequences.