Barakat syndrome diagnosed decades after initial presentation.

Summary: Barakat syndrome, also called HDR syndrome, is a rare genetic disorder encompassing hypoparathyroidism (H), sensorineural deafness (D) and renal disease (R). A 64-year-old woman was referred to our endocrinology clinic for a switch in treatment (from dihydrotachysterol to calcitriol). She had progressive sensorineural deafness since the age of 18 and idiopathic hypoparathyroidism diagnosed at age of 36. Her medical history included osteoporosis with hip/spine fractures, nephrolithiasis and a family history of hearing loss, osteoporosis and kidney disease. The patient's clinical presentation indicated Barakat syndrome. Genetic analysis found a GATA3:c.916C>T nonsense variant. Further tests such as audiometry, labs and renal imaging supported the diagnosis. Due to rarity and manifold symptoms, diagnosis can be challenging. Optional GATA3 testing was suggested in 2018, except in cases of isolated sensorineural deafness or renal disease with pertinent family history. In isolated 'H' cases without 'D' and 'R', GATA3 studies are not required, as no haploinsufficiency cases were reported. Given the rise in genetic disorders, physicians should consistently consider rare genetic disorders in patients with suggestive symptoms, even decades after onset. Although diagnosis might not always impact management directly, it aids patients in accepting their condition and has broader family implications. Learning points: There is currently an important increase in genetic and clinical characterization of new orphan diseases and their causative agents. Unbiased re-evaluation for possible genetic disorders is necessary at every consultation. It is essential to recognize the differential diagnosis of idiopathic hypoparathyroidism. The patient's clinical presentation and family history can be important to establish the correct diagnosis. Physicians should not hesitate to search a patient's signs and symptoms online.

A founder MLH1 mutation in Lynch syndrome families from Piedmont, Italy, is associated with an increased risk of pancreatic tumours and diverse immunohistochemical patterns.

The MLH1 c.2252_2253delAA mutation was found in 11 unrelated families from a restricted area south-west of Turin among 140 families with mutations in the mismatch repair genes. The mutation is located in the highly conserved C-terminal region, responsible for dimerization with the PMS2 protein. Twenty-five tumour tissues from 61 individuals with the c.2252_2253delAA mutation were tested for microsatellite instability (MSI) and protein expression. We compared the clinical features of these families versus the rest of our cohort and screened for a founder effect. All but one tumours showed the MSI-high mutator phenotype. Normal, focal and lack of MLH1 staining were observed in 16, 36 and 48 % of tumours, respectively. PMS2 expression was always lost. The mutation co-segregated with Lynch syndrome-related cancers in all informative families. All families but one fulfilled Amsterdam criteria, a frequency higher than in other MLH1 mutants. This was even more evident for AC II (72.7 vs. 57.5 %). Moreover, all families had at least one colon cancer diagnosed before 50 years and one case with multiple Lynch syndrome-related tumours. Interestingly, a statistically significant (p = 0.0057) higher frequency of pancreatic tumours was observed compared to families with other MLH1 mutations: 8.2 % of affected individuals versus 1.6 %. Haplotype analysis demonstrated a common ancestral origin of the mutation, which originated about 1,550 years ago. The mutation is currently classified as having an uncertain clinical significance. Clinical features, tissue analysis and co-segregation with disease strongly support the hypothesis that the MLH1 c.2252_2253delAA mutation has a pathogenic effect.

Inhibition of Src impairs the growth of met-addicted gastric tumors.

PURPOSE: We examined whether inhibition of Src tyrosine kinase, a downstream effector of the MET oncogene, can hinder the malignant properties of gastric tumors dependent on Met for growth and survival. EXPERIMENTAL DESIGN: Sensitivity to Src inhibition was determined in vitro by measuring clonogenic survival (anchorage-independent growth) and in vivo by establishing xenograft models. Four "Met-addicted" gastric carcinoma cell lines (GTL16, MKN45, HS746T, and SNU5) and three Met-independent gastric carcinoma cell lines (KATO III, AGS, and NCI-N87) were treated with the Src inhibitor saracatinib (AZD0530). In GTL16 and KATO III, Src neutralization was also achieved by dasatinib and RNA interference. The biochemical and transcriptional consequences of Src inhibition were explored using anti-phosphoprotein antibodies and oligonucleotide microarrays. RESULTS: Inhibition of Src in Met-addicted gastric carcinoma cell lines (a) decreased the phosphorylation/activation levels of signaling intermediates involved in cell proliferation and protection from apoptosis and down-modulated the expression of several cell cycle regulators; (b) reduced anchorage-independent growth; (c) enhanced impairment of cell viability produced by Met inhibition; and (d) delayed tumorigenesis in xenotransplantation models. Immunohistochemical analysis of tumor xenograft tissues following systemic treatment with saracatinib showed a reduction of tumor cell proliferation index, increased apoptosis, and diminished phospho-focal adhesion kinase and phospho-paxillin staining. Tumor stroma parameters such as angiogenesis or inflammatory infiltration were unaffected. In clonogenic survival assays, gastric carcinoma cells without addiction to Met were less sensitive than Met-addicted cells to Src inhibition. CONCLUSIONS: Src is as a key downstream transducer of Met-driven tumor growth. Targeting Src might provide therapeutic benefit in Met-addicted tumors.