Novel hereditary angioedema linked with a heparan sulfate 3-O-sulfotransferase 6 gene mutation.

BACKGROUND: Hereditary angioedema (HAE) is a potentially fatal disorder resulting in recurrent attacks of severe swelling. It may be associated with a genetic deficiency of functional C1 inhibitor or with normal C1 inhibitor (HAEnCI). In families with HAEnCI, HAE-linked mutations in the F12, PLG, KNG1, ANGPT1, or MYOF genes have been identified. In many families with HAEnCI the genetic cause of the disease is currently unknown. OBJECTIVE: The aim of this study was to identify a novel disease-linked mutation for HAEnCI. METHODS: The study methods comprised whole exome sequencing, Sanger sequencing analysis, pedigree analysis, bioinformatic analysis of the mutation, and biochemical analysis of parameters of the kallikrein-kinin (contact) system. RESULTS: By performing whole exome sequencing on a multigenerational family with HAEnCI we were able to identify the heparan sulfate (HS)-glucosamine 3-O-sulfotransferase 6 (HS3ST6) mutation c.430A>T (p.Thr144Ser) in all 3 affected family members who were sequenced. This gene encodes HS-glucosamine 3-O-sulfotransferase 6 (3-OST-6), which is involved in the last step of HS biosynthesis. The p.Thr144Ser mutation is likely to affect the interaction between 2 ß-sheets stabilizing the active center of the 3-OST-6 protein. CONCLUSIONS: We conclude that mutant 3-OST-6 fails to transfer sulfo groups to the 3-OH position of HS, resulting in incomplete HS biosynthesis. This likely affects cell surface interactions of key players in angioedema formation and is a novel mechanism for disease development.

[PAPA syndrome with Crohn's disease and primary sclerosing cholangitis/autoimmune hepatitis overlap syndrome]. / PAPA-Syndrom mit Morbus Crohn und primär sklerosierender Cholangitis/Autoimmunhepatitis-Overlap-Syndrom.

BACKGROUND: The PAPA syndrome, an acronym for pyogenic sterile arthritis, pyoderma gangraenosum and acne, is an autosomal dominant hereditary disease which is caused by a mutation in the PSTPIP1 ("proline-serine-threonine phosphatase interacting protein 1") gene located on chromosome 15 and encodes the proline-serine-threonine phosphatase-interacting protein 1. An association with Crohn's disease (CD), autoimmune diseases of the liver and PAPA syndrome has not yet been reported in the literature. OBJECTIVE: To thoroughly investigate a family with three affected members (mother and 2 children) with newly diagnosed PAPA syndrome and intestinal and hepatobiliary symptoms. MATERIAL AND METHODS: We performed an in-depth phenotyping, dermatologic, radiologic, rheumatologic, gastroenterologic, histologic and genetic analysis in this family. RESULTS: All three family members could be newly diagnosed as suffering from PAPA syndrome and carried the known disease-causing mutation c.688G > A (p.Ala230Thr) in the PSTPIP1 gene. The younger son suffered from CD in addition to PAPA syndrome. The mother additionally suffered from ulcerative colitis (UC) and an overlap syndrome between autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC). A mutation in in the NOD2 ("nucleotide binding oligomerization domain containing protein 2") gene could not be detected in any of the three persons affected. CONCLUSION: We extended the symptoms of PAPA syndrome to CD and autoimmune liver disease. These different disease entities might share a similar pathogenetic mechanism or even represent a new syndrome. This can be clarified in the future by screening patients with PAPA syndrome for intestinal and also hepatobiliary diseases.

Prevalence of hereditary transthyretin amyloid polyneuropathy in idiopathic progressive neuropathy in conurban areas.

BACKGROUND: Hereditary transthyretin amyloidosis (ATTR amyloidosis) is a rare, genetically heterogenous, and clinically variable autosomal dominant disease that severely reduces life expectancy. As treatment options grow, a proper diagnostic approach is mandatory especially in non-endemic regions with diverse genetic backgrounds. METHODS: We examined 102 neuropathy patients at a German neuromuscular centre. Common causes of polyneuropathy were ruled out by medical history and extensive laboratory testing to define a cohort of patients with progressive polyneuropathy classified as idiopathic. Molecular genetic testing of the entire TTR gene was performed, and the detected amyloidogenic and non-amyloidogenic variants were associated with the observed clinical phenotypes and results of prior diagnostic testing. RESULTS: Two of 102 patients tested positive for amyloidogenic mutations (p.Ile127Val and p.Glu81Lys), while a variant of unknown significance, p.Glu26Ser, was found in 10 cases. In both positive cases, previous negative biopsy results were proved by gene sequencing to be false negative. In case of the p.Glu81Lys mutation we detected clinical presentation (combination of severe polyneuropathy and cardiomyopathy), ethnic background (patient of polish origin, mutation only reported in Japanese families before), and disease course clearly differed from well-known cases of the same mutation in the literature. CONCLUSIONS: In conclusion, transthyretin hereditary amyloid polyneuropathy (ATTR-PN) should be considered in cases of otherwise idiopathic polyneuropathy. Sequencing of the four exons of the TTR gene should be considered the key step in diagnosis, while tissue biopsy possibly leads to false negative results.

Identification of the recently described plasminogen gene mutation p.Lys330Glu in a family from Northern Germany with hereditary angioedema.

Hereditary angioedema (HAE) is a life-threatening disease characterized by recurrent episodes of subcutaneous and mucosal swellings and abdominal cramping. Corticosteroids and antihistamines, which are usually beneficial in histamine-induced acquired angioedema, are not effective in HAE. Therefore, diagnosing HAE correctly is crucial for affected patients. We report a family from Northern Germany with six individuals suffering from recurrent swellings, indicating HAE. Laboratory tests and genetic diagnostics of the genes SERPING1, encoding C1 esterase inhibitor (C1-INH), and F12, encoding coagulation factor XII, were unremarkable. In three affected and one yet unaffected member of the family, we were then able to identify the c.988A > G (also termed c.1100A > G) mutation in the plasminogen (PLG) gene, which has recently been described in several families with HAE. This mutation leads to a missense mutation with an amino acid exchange p.Lys330Glu in the kringle 3 domain of plasminogen. There was no direct relationship between the earlier described cases with this mutation and the family we report here. In all affected members of the family, the symptoms manifested in adulthood, with swellings of the face, tongue and larynx, including a fatal case of a 19 year-old female individual. The frequency of the attacks was variable, ranging between once per year to once a month. In one individual, we also found decreased serum levels of plasminogen as well as coagulation factor XII. As previously reported in patients with PLG defects, icatibant proved to be very effective in controlling acute attacks, indicating an involvement of bradykinin in the pathogenesis.

Mixed leukocyte cell-derived chemotaxin 2 and amyloid A renal amyloidosis in a Kazakh-German patient.

Leukocyte cell-derived chemotaxin 2 (LECT2)-related amyloidosis (ALECT2) constitutes a subtype of systemic amyloidosis affecting the kidney. This is the first case describing mixed ALECT2 and Amyloid A renal amyloidosis in a Kazakh-German patient. Genetic analysis shows a polymorphism in the LECT2 gene and a homozygous mutation in the SAA1 gene. Notably, our patient has a body mass index of 61 kg/m2 and a pathological glucose tolerance test. ALECT2 was found in certain ethnic groups with a high incidence of diabetes. In our case, morbid obesity may have played a significant role in clinical manifestation of ALECT2 amyloidosis.