Two consecutive severe prekallikrein deficiencies were investigated. The first was identified in a 63-year-old patient admitted for ischemic stroke. The second deficiency was identified in a 38-year-old patient admitted for a second-trimester pregnancy loss. A homozygous C529Y mutation was identified for both cases, whereas they are unrelated and no consanguineous marriage is known from the patients. These data point to a possible high frequency of this mutation as a cause of prekallikrein deficiency.

Factor XI (FXI) deficiency is an inherited autosomal recessive disorder associated with bleeding of variable severity. However, many cases of dominant disease transmission have been recently described. This disorder is rare in the general population, whereas it is commonly found in individuals of Ashkenazi Jewish ancestry. This study reports the molecular genetic analysis of FXI deficiencies in 11 unrelated families of different origin. Five novel mutations have been identified. Severe FXI deficiency of two unrelated patients resulted from two novel mutations: one deletion (960-961delGT) in exon 9 predicting a frameshift, and a Ser-4Leu mutation located in the signal peptide. In addition, three novel missense mutations associated with partial FXI deficiency have been identified: Cys122Tyr, Glu297Lys and Glu579Lys.

A congenital FXIII A subunit deficiency was diagnosed in a male child because of umbilical bleeding at birth. Venous infusion was difficult and prophylactic FXIII infusion was delayed. At age 1, he suffered a spontaneous intracranial haemorrhage. Substitutive FXIII was initiated, and at age 12, no other significant bleeding event had occurred. His 5 years younger brother also bears the same FXIII deficiency. The younger brother's treatment was initiated at birth and never discontinued, and no bleeding occurred. Mutation gene analysis found a homozygous four bases insertion predicting a stop codon seven residues after PRO675. Antigen assay indicated that the mutant molecule is secreted. This case highlights the importance of prophylactic FXIII infusion.

Ehlers-Danlos syndromes (EDS) are a heterogeneous group of hereditary connective tissue disorders (HTCD) caused by mutations in genes involved in the structure and/or biosynthesis of collagens and other extracellular matrix proteins. 1 The 2017 classification consists of 13 types of EDS based on clinical manifestations and genetic abnormalities in 19 different genes. 2 Main common characteristics are generalized joint hypermobility (GJH), skin hyperextensibility, and tissue fragility. Scoliosis is another common manifestation in EDS patients. 1,3,4 Especially,