Associations between Dietary Intake, Blood Levels of Omega-3 and Omega-6 Fatty Acids and Reading Abilities in Children.

Lower levels of omega-3 polyunsaturated fatty acids (PUFAs) have been described in individuals with reading difficulties, but the degree and the nature of such deficiencies as well as the role of nutrition are a matter of debate. The aim of the present study was to investigate the associations between PUFA blood levels, nutritional status, and reading/writing/phonological awareness performances in 42 school-age children with varying levels of reading ability. Significant correlations were found between PUFA levels (specific omega-6/omega-3 ratios), the ratio of omega-6-derived calories to the total amount of calories and reading scores. Mediation analysis showed a mediating effect of fatty acids on the association between reading speed scores and nutritional status. Moderation analysis, moreover, showed that the associations of omega-6/omega-3 ratios in the blood and Kcal omega-6/Kcal total in dietary intake were moderated by reading speed performances. Results of the mediation and moderation models confirm that the associations of dietary intake with PUFA levels in the blood vary depending on learning abilities. Reading skills appear to be sensitive to the effects of a complex set of favorable conditions related to the presence of higher omega-3 blood levels. These conditions may reflect the action of dietary as well as genetic and epigenetic mechanisms.

Pro-resolving and pro-inflammatory fatty acid-derived mediators in sputum of stable state bronchiectasis patients.

BACKGROUND: Bronchiectasis is characterized by neutrophilic inflammation and frequent exacerbations often associated with infections. Lipid mediators play critical roles in the inflammatory response, and the balance between anti-inflammatory and pro-inflammatory mediators could drive to chronic inflammation. The aim of this study was to evaluate the metabolites of docosahexaenoic acid and arachidonic acid in sputum of adults with bronchiectasis defining their associations with clinical data, bacterial load and neutrophil elastase. METHODS: An observational, cross-sectional study was conducted at the bronchiectasis program of the Policlinico Hospital in Milan, Italy, where patients were enrolled. Active neutrophil elastase was measured by enzyme-linked immunosorbent assay, pro-resolving and pro-inflammatory fatty acid-derived mediators were evaluated by mass spectrometry and respiratory pathogens were assessed by real-time PCR. Analysis were performed on sputum collected during stable state and clinical data were also collected. RESULTS: Levels of pro-inflammatory mediators derived from arachidonic acid metabolism showed association with neutrophil elastase, were proportional to Pseudomonas aeruginosa identifications and were linked with radiological gravity index, while the concentrations of pro-resolution mediators derived from docosahexaenoic acid were associated with a better health status, highlighted by the inverse correlation with radiological gravity index, bacterial infections and sputum volume production. CONCLUSION: Pro-inflammatory mediators derived from FA metabolisms are associated with severity of bronchiectasis while DHA-derived metabolites are inversely associated with severity of the disease, which may be used for personized treatment of bronchiectasis.

Comparative Analysis of Docosahexaenoic Acid (DHA) Content in Mother's Milk of Term and Preterm Mothers.

Objectives and Study: Docosahexaenoic acid (DHA) plays an essential role in infants' development. Maternal diet and breastmilk are the primary DHA sources for newborns. This single-center observational study aimed to compare the DHA content in mother's milk of preterm mothers with that of term ones, and to investigate the changes in mother's milk DHA content according to the week of the gestational age. Methods: A food frequency questionnaire (FFQ) was submitted to each mother to estimate the DHA intake during the last trimester of pregnancy, and the mother's milk was collected between 24 and 96 h post-partum. Results: Women who gave birth prematurely showed a lower content of mother's milk DHA than the term ones (0.51; IQR 0.38−0.6% FA vs. 0.71; IQR 0.52−0.95% FA; p = 0.001). In the multivariate linear regression analyses, for each additional week of gestational age, there was an increase in DHA content in the mother's milk (0.046% FA; CI 95% 0.018−0.074; p < 0.001). Conclusions: Our results suggest that breast milk may not be sufficient to fully satisfy the recommended DHA intake in preterm infants. This study may represent a starting point to investigate new possible DHA supplementation strategies, especially for the late and moderate preterm infants.

Long-Chain Polyunsaturated Fatty Acids Supplementation and Respiratory Infections.

BACKGROUND: Long-chain polyunsaturated fatty acids (LCPUFAs) can actively affect the maintenance and optimal functioning of immune cells. The metabolites of both omega-3 and omega-6 play an important role in the synthesis of different mediators, such as prostaglandins, leukotrienes, thromboxanes, protectins, and resolvins, that can interfere with the virus and modulate inflammation. SUMMARY: In this narrative review, we aim to identify whether LCPUFA supplementation may be effective in protecting the population against respiratory tract infections. We included only randomized controlled trials performed in both pediatric and adult subjects. Eight papers were selected: five trials were conducted in a pediatric population and three in adults. Different concentrations of fatty acids supplementation were associated with a lower incidence of common respiratory symptoms, except for two studies that did not provide significant results. Most of the studies are of low quality, and respiratory infections were assessed as secondary or even safety outcomes. KEY MESSAGES: No data were available on the role of LCPUFAs in coronavirus disease 2019 (COVID-19). Although these data showed that LCPUFAs may be effective in preventing respiratory tract infections, future studies are still needed to clarify their possible co-adjuvant role in the prevention and treatment of respiratory infections.

Whole blood fatty acid profile of young subjects and adherence to the Mediterranean diet: an observational cohort study.

BACKGROUND: Relatively little is known about the physiological whole blood fatty acid composition in young people. Likewise, few studies have addressed the question of correlations between Mediterranean diet (MedDiet) adherence and blood fatty acids in childhood. METHODS: The fatty acid profile in whole blood from subjects, 46 days-19 years old (n = 152), without acute, chronic, or inflammatory diseases was analysed by gas chromatography. Dietary data was extracted from a 24-h recall in a subgroup of subjects (n = 60) into a modified Diet Quality Index for Children (KIDMED) questionnaire to evaluate MedDiet adherence. The cohort was divided into three age groups: < 2, 2- < 10, and 10-19 years. Kruskal-Wallis test and Bonferroni post hoc test were used to check for age group fatty acid differences. For correlations, Spearman's correlation coefficient and partial Spearman's correlation coefficient were used. RESULTS: Linoleic acid, EPA, DHA, palmitic acid, and total saturated fatty acids were stable over age groups. Dihomo-gamma-linolenic acid (DGLA), arachidonic acid (AA), total polyunsaturated FAs (PUFA), and total omega-6 PUFA increased from age group < 2 years; alpha-linolenic acid, total omega-3 PUFA, oleic acid, and total monounsaturated FAs decreased. Adherence to the MedDiet was at low-medium level in 91.7% of the subjects. In the age group 2- < 10 yrs., the degree of adherence correlated positively with total MUFA and PUFA balance, negatively with total PUFA, total n6-PUFA, AA/DHA, AA/EPA, and n6/n3. Age did not influence the correlations as to PUFA balance and AA/EPA. CONCLUSIONS: Increased FA proportions with age were seen in the n6-series of PUFA. The n3-FA species decreased or were stable. The vast majority of the subjects with dietary data, 92%, obtained a KIDMED score indicative of low-medium adherence to the MedDiet. The score correlated negatively with various n6-species, i.e. the MedDiet suppressed circulating n6-PUFA. Whole blood may be used to investigate FAs and MedDiet adherence correlations which may be applied in the study of health issues in childhood.

Direct and Indirect Effects of Blood Levels of Omega-3 and Omega-6 Fatty Acids on Reading and Writing (Dis)Abilities.

The purpose of the present study was to investigate whether there are associations between polyunsaturated fatty acid (PUFA) blood levels, reading/writing performance and performance in neuropsychological tasks. Moderate to strong correlations were found between PUFA levels (specific omega-6/omega-3 ratios) and reading/writing abilities, and the former and neuropsychological test scores. Mediation models analyzing the direct and indirect effects of PUFA on reading and writing scores showed that the effects of fatty acids on learning measures appear to be direct rather than mediated by the investigated visual and auditory neuropsychological mechanisms. The only significant indirect effect was found for the difference in accuracy between the left and right visual fields in visual-spatial cueing tasks, acting as a mediator for the effect of PUFA ratios on writing accuracy. Regression analyses, by contrast, confirmed the roles of phonological awareness and other visual attentional factors as predictors of reading and writing skills. Such results confirm the crucial role of visual-spatial attention mechanisms in reading and writing, and suggest that visual low-level mechanisms may be more sensitive to the effects of favorable conditions related to the presence of higher omega-3 blood levels.

Role of Arachidonic Acid and Its Metabolites in the Biological and Clinical Manifestations of Idiopathic Nephrotic Syndrome.

Studies concerning the role of arachidonic acid (AA) and its metabolites in kidney disease are scarce, and this applies in particular to idiopathic nephrotic syndrome (INS). INS is one of the most frequent glomerular diseases in childhood; it is characterized by T-lymphocyte dysfunction, alterations of pro- and anti-coagulant factor levels, and increased platelet count and aggregation, leading to thrombophilia. AA and its metabolites are involved in several biological processes. Herein, we describe the main fields where they may play a significant role, particularly as it pertains to their effects on the kidney and the mechanisms underlying INS. AA and its metabolites influence cell membrane fluidity and permeability, modulate platelet activity and coagulation, regulate lymphocyte activity and inflammation, preserve the permeability of the glomerular barrier, influence podocyte physiology, and play a role in renal fibrosis. We also provide suggestions regarding dietary measures that are able to prevent an imbalance between arachidonic acid and its parental compound linoleic acid, in order to counteract the inflammatory state which characterizes numerous kidney diseases. On this basis, studies of AA in kidney disease appear as an important field to explore, with possible relevant results at the biological, dietary, and pharmacological level, in the final perspective for AA to modulate INS clinical manifestations.

Bioactive Compounds in Edible Oils and Their Role in Oxidative Stress and Inflammation.

Diet and inflammatory response are recognized as strictly related, and interest in exploring the potential of edible fats and oils for health and chronic diseases is emerging worldwide. Polyunsaturated fatty acids (PUFAs) present in fish oil (FO), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may be partly converted into oxygenated bioactive lipids with anti-inflammatory and/or pro-resolving activities. Moreover, the co-presence of phenolic compounds and vitamins in edible oils may prevent the development of chronic diseases by their anti-inflammatory, antioxidant, neuroprotective, and immunomodulatory activities. Finally, a high content in mono-unsaturated fatty acids may improve the serum lipid profile and decrease the alterations caused by the oxidized low-density lipoproteins and free radicals. The present review aims to highlight the role of lipids and other bioactive compounds contained in edible oils on oxidative stress and inflammation, focusing on critical and controversial issues that recently emerged, and pointing to the opposing role often played by edible oils components and their oxidized metabolites.

Persistent Abnormalities of Fatty Acids Profile in Children With Idiopathic Nephrotic Syndrome in Stable Remission.

Steroid-sensitive nephrotic syndrome is an immunological disorder mediated by still poorly defined circulating factor(s) that target the podocyte and damage the filtration barrier. Fatty acids (FA) have several biological roles and, in particular, are strictly involved in cell to cell communication, inflammatory processes and regulation of lymphocyte pools. Studies of FAs during INS have been mainly focused on biochemical changes during the phase of proteinuria; while no information is available about FA profile in patients with idiopathic nephrotic syndrome (INS) on stable remission. Aim of this study is to assess differences in blood FA profile between pediatric patients with INS during the phase of stable remission. Blood fatty acid profile of 47 pediatric patients on stable remission and 47 matched healthy controls were evaluated with gas chromatography. Patients with INS on stable remission had significantly higher levels of PUFA and omega-6 than controls (40.17 vs. 37.91% and 36.95 vs. 34.79%), lower levels of SFA and MUFA. Considering the single fatty acids, levels of omega-6 18:2n6 linoleic acid and omega-6 20:4n6 arachidonic acid were significantly higher in patients with INS than in controls (23.01 vs. 21.55%, p-value 0.003 and 10.37 vs. 9.65%, p-value 0.01). Moreover, patients with INS showed lower levels of SFA 14:0 (0.74 vs. 0.92%) and 18:0 (10.74 vs. 11.74%) and MUFA 18:1n9 oleic acid (18.50 vs. 19.83%). To the best of our knowledge this is the first study assessing FAs profile in children with INS in stable remission. In a population of 47 patients, we were able to demonstrate a higher blood level of linoleic and arachidonic acid, and consequently of omega-6 and PUFA, compared to controls. Persistently higher than normal levels of either linoleic or arachidonic acid, could be viewed as candidate biomarker for a state of risk of relapse in children with idiopathic nephrotic syndrome.

N-3 Polyunsatured Fatty Acids in Menopausal Transition: A Systematic Review of Depressive and Cognitive Disorders with Accompanying Vasomotor Symptoms.

Depression is one of the most important health problems worldwide. Women are 2.5 times more likely to experience major depression than men. Evidence suggests that some women might experience an increased risk for developing depression during "windows of vulnerability", i.e., when exposed to intense hormone fluctuations, such as the menopause transition. Indeed, this period is associated with different symptoms, including vasomotor, depressive, and cognitive symptoms, which have all been shown to worsen as women approach menopause. Even though hormonal therapy represents the most effective treatment, side effects have been reported by several studies. Therefore, an increased number of women might prefer the use of alternative medicine for treating menopausal symptoms. N-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) are included among these alternative treatments. We here provide a review of studies investigating the effects of n-3 LCPUFAs on hot flashes and depressive and cognitive disorders in menopausal women. The reported results are scattered and heterogeneous. In conclusion, a beneficial role of n-3 LCPUFAs in hot flashes, and depressive and cognitive symptoms related to menopausal transition is still far from conclusive.

The polyunsaturated fatty acid balance in kidney health and disease: A review.

Epidemiological studies show that circulating polyunsaturated fatty acids contribute to preserve renal function. In renal disease states there is generally a lack of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) as measured in biological samples, but despite intense research for more than 30 years, it is still unclear how and to what extent their supplementation would benefit kidney disorders. Studies evaluating the n-6 series and the kidney are less frequent. The last compilation of clinical trials with n-3 LCPUFA supplements focusing on renal function and damage dates back to 2012. We here discuss n-3 and n-6 fatty acids in relation to the kidney summarizing single- and double blind randomized controlled trials performed between 2012 and 2016. Nine were sub-studies/post-hoc analyses of previous parent trials. Twelve out of the twenty trials reported on fatty acid profile or fatty acid species. Factors that may explain inconsistent results obtained after supplementation with the n-3 LCPUFA EPA and DHA in kidney disease are discussed such as baseline levels determining response, drug interaction. The need of evaluating fatty acid status before and after intervention is emphasized, to match changes in outcome measure with changes of any fatty acid potentially involved.

Fatty Acids in Nephrotic Syndrome and Chronic Kidney Disease.

The role of fatty acids (FAs) in inflammation and in the related chronic diseases has been demonstrated. However, there is a lack of consistent and agreed knowledge about the role of FA profile and renal physiology and pathology, most articles focusing on the effect of polyunsaturated FAs supplementation, without considering the impact of basal FA metabolism on the efficacy of the supplementation. Here, we have summarized the specific literature concerning the assessment of circulating FA in 2 renal diseases, namely nephrotic syndrome and chronic kidney disease, also under hemodialytic treatment, and have received the most significant contributions in the last years. The effects of changes of FA profile and metabolism and the possible involvement of polyunsaturated FA metabolites in raising and modulating inflammation are discussed.

ABCB4 mutations in adult patients with cholestatic liver disease: impact and phenotypic expression.

BACKGROUND: The ABCB4 gene encodes the MDR3 protein. Mutations of this gene cause progressive familial intrahepatic cholestasis type 3 (PFIC3) in children, but their clinical relevance in adults remains ill defined. The study of a well-characterized adult patient series may contribute to refining the genetic data regarding cholangiopathies of unknown origin. Our aim was to evaluate the impact of ABCB4 mutations on clinical expression of cholestasis in adult patients. METHODS: We consecutively evaluated 2602 subjects with hepatobiliary disease. Biochemical evidence of a chronic cholestatic profile (CCP) with elevated serum gamma-glutamyltransferase activity or diagnosis of intrahepatic cholestasis of pregnancy (ICP) and juvenile cholelithiasis (JC) were inclusion criteria. The personal/family history of additional cholestatic liver disease (PFH-CLD), which includes ICP, JC, or hormone-induced cholestasis, was investigated. Mutation screening of ABCB4 was carried out in 90 patients with idiopathic chronic cholestasis (ICC), primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC), ICP, and JC. RESULTS: Eighty patients had CCP. PSC and ICC patients with PFH-CLD had earlier onset of disease than those without it (p = 0.003 and p = 0.023, respectively). The mutation frequency ranged from 50% (ICP, JC) to 17.6% (PBC). Among CCP patients, presence or absence of PFH-CLD was associated with ABCB4 mutations in 26.8 vs 5.1% (p = 0.013), respectively; in the subset of ICC and PSC patients, the corresponding figures were 44.4 vs 0% (p = 0.012) and 28.6 vs 8.7% (p = 0.173). CONCLUSIONS: Cholangiopathies attributable to highly penetrant ABCB4 mutant alleles are identifiable in a substantial proportion of adults that generally have PFH-CLD. In PSC and ICC phenotypes, patients with MDR3 deficiency have early onset of disease.

Urinary exosomes in the diagnosis of Gitelman and Bartter syndromes.

BACKGROUND: Gitelman syndrome (GS) and Bartter syndrome (BS) are hereditary salt-losing tubulopathies (SLTs) resulting from defects of renal proteins involved in electrolyte reabsorption, as for sodium-chloride cotransporter (NCC) and furosemide-sensitive sodium-potassium-chloride cotransporter (NKCC2) cotransporters, affected in GS and BS Type 1 patients, respectively. Currently, definitive diagnosis is obtained through expensive and time-consuming genetic testing. Urinary exosomes (UE), nanovesicles released by every epithelial cell facing the urinary space, represent an ideal source of markers for renal dysfunction and injury, because UE molecular composition stands for the cell of origin. On these assumptions, the aim of this work is to evaluate the relevance of UE for the diagnosis of SLTs. METHODS: UE were purified from second morning urines collected from 32 patients with genetically proven SLTs (GS, BS1, BS2 and BS3 patients), 4 with unclassified SLTs and 22 control subjects (age and sex matched). The levels of NCC and NKCC2 were evaluated in UE by SDS-PAGE/western blotting with specific antibodies. RESULTS: Due to their location on the luminal side of tubular cells, NCC and NKCC2 are well represented in UE proteome. The NCC signal is significantly decreased/absent in UE of Gitelman patients compared with control subjects (Mann-Whitney t-test, P < 0.001) and, similarly, the NKCC2 in those of Bartter type 1 (P < 0.001). The difference in the levels of the two proteins allows recognition of Gitelman and Bartter type 1 patients from controls and, combined with clinical data, from other Bartter patients. Moreover, the receiver operating characteristic curve analysis using UE NCC densitometric values showed a good discriminating power of the test comparing GS patients versus controls and BS patients (area under the curve value = 0.92; sensitivity 84.2% and specificity 88.6%). CONCLUSIONS: UE phenotyping may be useful in the diagnosis of GS and BS, thus providing an alternative/complementary, urine-based diagnostic tool for SLT patient recognition and a diagnostic guidance in complex cases.

Type III Bartter-like syndrome in an infant boy with Gitelman syndrome and autosomal dominant familial neurohypophyseal diabetes insipidus.

We report the case of an infant boy with polyuria and a familial history of central diabetes insipidus. Laboratory blood tests disclosed hypokalemia, metabolic alkalosis, hyperreninemia, and hyperaldosteronism. Plasma magnesium concentration was slightly low. Urine analysis showed hypercalciuria, hyposthenuria, and high excretion of potassium. Such findings oriented toward type III Bartter syndrome (BSIII). Direct sequencing of the CLCNKB gene revealed no disease-causing mutations. The water deprivation test was positive. Magnetic resonance imaging showed a lack of posterior pituitary hyperintensity. Finally, direct sequencing of the AVP-NPII gene showed a point mutation (c.1884G>A) in a heterozygous state, confirming an autosomal dominant familial neurohypophyseal diabetes insipidus (adFNDI). This condition did not explain the patient's phenotype; thus, we investigated for Gitelman syndrome (GS). A direct sequencing of the SLC12A3 gene showed c.269A>C and c.1205C>A new mutations. In conclusion, the patient had a genetic combination of GS and adFNDI with a BSIII-like phenotype.

Renal phosphate handling in Gitelman syndrome--the results of a case-control study.

BACKGROUND: Patients with Gitelman syndrome, a hereditary salt-wasting tubulopathy, have loss-of-function mutations in the SLC12A3 gene coding for the thiazide-sensitive sodium chloride co-transporter in the distal convoluted tubule. Since the bulk of filtered phosphate is reabsorbed in the proximal tubule, renal phosphate wasting is considered exceptional in Gitelman syndrome. METHODS: We investigated the renal handling of inorganic phosphate in 12 unselected Italian patients affected with Gitelman syndrome (5 females and 7 males, aged 6.0-18 years, median age 12 years) and in 12 healthy subjects matched for gender and age (controls). The diagnosis of Gitelman syndrome among the patients had been made clinically and confirmed by molecular biology studies. RESULTS: The biochemical hallmarks of Gitelman syndrome, namely hypochloremia, hypokalemia, hypomagnesemia, increased urinary excretion of sodium, chloride, potassium and magnesium and reduced urinary excretion of calcium, were present in the 12 patients. In addition, both the plasma inorganic phosphate concentration (median and interquartile range: 1.28 [1.12-1.36] vs. 1.61 [1.51-1.66)] mmol/L) and the maximal tubular reabsorption of inorganic phosphate (1.08 [0.99-1.22] vs. 1.41 [1.38-1.47] mmol/L) were significantly lower (P < 0.001) in Gitelman patients than in control subjects. Circulating levels of 25-hydroxyvitamin D, intact parathyroid hormone and osteocalcin were similar in patients and controls. CONCLUSIONS: The results of our case-control study disclose a hitherto unrecognized tendency towards renal phosphate wasting with mild to moderate hypophosphatemia in Gitelman syndrome.

Living with Gitelman disease: an insight into patients' daily experiences.

BACKGROUND: Gitelman disease presents with musculoskeletal complaints and fatigue. Surprisingly, there is no clear-cut correlation between biochemical abnormalities and symptoms. METHODS: Starting from the hypothesis that the way patients comprehend their illness within their sociocultural frameworks reflects on their way of adapting to it, this study investigated how adult patients experience the disease in everyday life. We conducted a qualitative analysis based on interviews with 12 patients. Interviews were audio recorded, fully transcribed and analyzed using the constant comparative method described by Strauss and Corbin. RESULTS: A typology of the experiences emerged from the data and was tested on each transcript with an explicit search for disconfirming cases. Patients fell into four main groups: (i) those considering Gitelman disease a disabling illness, (ii) those considering it a normalized illness, (iii) those considering it a different normality and (iv) those considering it an episodic disability. Each pattern of experience was characterized by particular (i) ways of interpreting symptoms (ii) ways of managing Gitelman disease in everyday life, (iii) general lifestyles and (iv) risks for the patient's psychosocial life. CONCLUSIONS: These findings suggest that health care providers should take advantage of considering patients' own perception of the disease in order to adjust the care and advice provided.

The mutation c.1196_1202dup7bp (p.Ser402X) in the SLC12A3 gene clusters in Italian Gitelman syndrome patients and reflects the presence of a common ancestor.

BACKGROUND: Inactivating mutations in the SLC12A3 gene are the main cause of Gitelman's syndrome (GS), a renal tubular disorder inherited as an autosomal recessive trait. In our cohort of patients, we identified 11 probands from 11 apparently unrelated Italian families that carry the c.1196_1202dup7bp mutation, which appears to be more frequent than other mutations in Italian GS patients. Therefore, we characterized in greater detail the SLC12A3 locus and its vicinity in those patients that carry this mutation in order to detect a possible shared haplotype. Three further probands characterized in France, carrying the same mutation, were also included in this study. METHODS: Sequence or fragment analyses were carried out to investigate seven intragenic polymorphisms (rs3217425, rs3816119, rs2304483, rs2278490, rs2278489, rs2289116 and rs2289115) that flank the mutation, as well as two extragenic markers, D16S3071 and D16S3057, flanking the SLC12A3 locus in the 5' and 3' termini, respectively. RESULTS: A shared haplotype co-segregates with the mutation both in Italian and French probands. Moreover, all the Italian families originate from a restricted area of Italy. Likewise, the French probands come from an area of France close to the north of Italy. CONCLUSION: It is likely that the c.1196_1202dup7bp mutation in the SLC12A3 gene reflects the presence of a common ancestor in an area covering the northern-central part of Italy and eastern France. A modified genotyping strategy for GS patients originating from this area has to be considered.

Early appearance of hypokalemia in Gitelman syndrome.

Inactivating mutations in the SLC12A3 gene that encodes the thiazide-sensitive co-transporter causes Gitelman syndrome. The main features of this syndrome include normal or low blood pressure, hypokalemia, metabolic alkalosis, hypomagnesemia, hypocalciuria, and hyperreninemia. These patients are at low risk for preterm birth and do not present with symptoms before school age. As a consequence, the condition is usually diagnosed in late childhood or in adult life. We report on four patients, two pairs of prematurely born twins, in whom hypokalemia was demonstrated early in life. In these children, a tendency towards hypokalemia was first noted during the third week of life. Overt hypokalemia subsequently appeared associated with normal blood pressure, hypochloremia, hyperreninemia, and an inappropriately high fractional excretion of potassium and chloride. Molecular biology studies failed to detect mutations in the SLC12A1, KCNJ1, and CLCNKB genes responsible for the Bartter syndromes type I, II and III, respectively. Compound heterozygous mutations in the SLC12A3 gene were detected in both pairs of twins: a frameshift mutation in exon 10 (c.1196_1202dup7bp), leading to the truncated protein p.Ser402X, and a missense mutation in exon 11, p.Ser475Cys (c.1424C>G) in the first pair; two missense mutations, p.Thr392Ile (c.1175C>T) in exon 9 and p.Ser615Leu in exon 15 (c.1844C>T), in the second pair. In conclusion, the diagnosis of Gitelman syndrome deserves consideration in infants with unexplained hypokalemia.