Idiopathic toe walking and heterozygous mutation in the NDGR1 gene: 2 clinical cases

В данной статье приводится описание двух клинических случаев пациенток с ходьбой на носках. В рамках диагностики обеим пациенткам был проведен генетический тест на наследственную сенсомоторную нейропатию, который выявил у одной пациентки мутацию в гене NDRG1 с редким вариантом c.1022G> A; p.arg341His (частота минорного аллеля < 0,01%), у другой пациентки обнаружен гетерогенный вариант c.1053_1082del и NM_001135242.1 p.Thr360_Gly369del. Данные мутации ассоциированы с болезнью Шарко–Мари–Тута (тип 4D), но ни у одной из пациенток клинически не было обнаружено данной наследственной нейропатии, в то же время диагноз идиопатической ходьбы на носках также сомнителен, поскольку в обоих случаях потребовалось достаточно серьезное лечение. Поэтому разумно предположить, что обе пациентки ходят на цыпочках по генетической причине. This article describes two clinical cases of patients with tiptoe walking. As part of the diagnosis, both patients underwent a genetic test for hereditary sensorimotor neuropathy, which revealed in one patient a mutation in the NDRG1 gene with a rare variant c.1022G> A; p.arg341his (minor allele frequency < 0.01%), in the other patient a heterogeneous variant c.1053_1082del and NM_001135242.1 p.thr360_gly369del was detected. These mutations are associated with Charcot–Marie–Toute disease (type 4D), but none of the patients were clinically diagnosed with this hereditary neuropathy, while the diagnosis of idiopathic toe-walking is also doubtful, since in both cases quite serious treatment was required. Therefore, it is reasonable to assume that both patients walk on tiptoe for a genetic reason.

Clinical and genetic characteristics of Charcot–Marie–Tooth disease type 4D (type Lom) in Russia

Introduction. Charcot–Marie–Tooth disease type 4D is a hereditary demyelinating neuropathy, that occurs with the high frequency in patients of Roma origin. It is characterized by early onset at the age of 2–10 years and hearing impairment, manifested by the 3rd decade of life.Aim of the study. To describe the clinical and genetic characteristics of Charcot–Marie–Tooth disease type 4D in Russian patients of Roma origin.Materials and methods. For 14 probands from unrelated families of Roma origin with a clinical diagnosis of Charcot–Marie–Tooth disease, genetic tests for the pathogenic variants c. 442C>T in the NDRG1 gene and c. 3325C>T in the SH3TC2 gene was carried out. For 8 patients with Charcot–Marie–Tooth disease type 4D, detailed clinical and electrophysiological examination was performed.Results. In 11 families of Roma origin, the c. 442C>T pathogenic variant in the NDRG1 gene in a homozygous state was detected, which accounted for 79 % all observed Roma patients with Charcot–Marie–Tooth disease. There are 12 of the 14 tested families live in the European part of Russia, 7 of them are from nearby regions. The average age of onset was 3.3 years. The first symptom in 7 of 8 patients was gait disturbances. At the time of examination (age range 6–19 years), all patients showed marked hypotrophy and weakness of the feet, lower leg, hands muscles, feet deformities, reduction or loss of tendon reflexes.Discussion. Due to the detection of only one pathogenic variant in most Russian patients of Roma origin with Charcot–Marie–Tooth disease, the knowledge of the ethnicity of a proband with early myelinopathy can significantly simplify the confirmation of the diagnosis on the molecular level.

Correlation between NDRG1 gene polymorphism and neuropathy (N) in metastatic breast cancer (MBC) patients (pts) enrolled in the PAINTER study (Polymorphism And INcidence of Toxicity in ERibulin treatment).

3116 Background: MBC is an incurable disease and therefore treatment focuses mainly on prolonging pts survival and improving quality of life. Eribulin (E) is a microtubule inhibitor that increased overall survival in pretreated pts. E peripheral N is reported in 13.9-35% of cases. PAINTER main objective was to survey tolerability of E in real life in MBC, while secondary endpoints were to investigate the relationships between specific genetic polymorphisms and incidence and severity of peripheral N. Methods: This is a multicenter, interventional, single-arm, phase IV study, that enrolled pts who received E after taxanes and antracyclines (dose 1.4 mg/m2 day 1, 8 every 21 days). PAINTER study follow-up is still ongoing. Genomic DNA was isolated from whole blood samples (Maxwell whole blood DNA kit. Promega). 15 SNPs (Single Nucleotide Polymorphisms) were genotyped by Taqman specific assays. For SNPs analysis, we selected pts with avaliable clinical data and who completed E treatment. N was evaluated by medical examination. The associations between peripheral N (any grade) and the selected polymorphisms were evaluated with Fisher exact test. Results: From May 2014 to June 2018, 180 pts were enrolled in the PAINTER study from 20 Italian hospitals and 135 were analysed for the present report. Pts and tumor characteristics were as follow: median age 62 years (31-85), ductal carcinoma 78.5%, visceral disease 70.4%, luminal type 62.6%, Her2 positive 20.3%, triple negative 17.1%, previous median treatment lines for MBC 5 (0-18), previous N reported in 17.8% of pts (sensory 87.5%, motor 12.5%). N (all grades) were reported in 33.4% of patients (G3-G4: 3%). Among the selected SNPs, one allelic variant (rs2233335 G/G versus G/T or T/T) in NDRG1 gene had a statistically significant association with N (p 0.0010). Conclusions: The data reported demonstrate for the first time that the allelic variant rs2233335 (G/T and T/T) in NDRG1 gene correlates with E induced N. These data, if corroborated, will allow a tailored treatment with E. Clinical trial information: NCT02864030. [Table: see text]

N-myc downstream regulated 1 gene and its place in the cellular machinery.

The exact function of the protein product of N-myc downstream regulated 1 gene (NDRG1) is unclear. Depending on the tissue type the NDRG1 protein is localized in the cytoplasm, nucleus, mitochondrion or membranes. Moreover, the expression of NDRG1 may be altered by several factors such as hypoxia, heavy metals, DNA damage, hormones, oncogene, and tumor-suppressor genes. A number of studies emphasize the role of NDRG1 in cancerogenesis. Presumably NDRG1 participates in angiogenesis, metastases, and mechanisms leading to anti-cancer drug resistance. This review summarizes current knowledge about the NDRG1 gene and the position of NDRG1 protein in the cellular machinery. The role of NDRG1 in cancer pathogenesis and its possible usefulness as a prognostic factor for patients with cancer is also discussed.