A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067.

Planets with radii between that of the Earth and Neptune (hereafter referred to as 'sub-Neptunes') are found in close-in orbits around more than half of all Sun-like stars1,2. However, their composition, formation and evolution remain poorly understood3. The study of multiplanetary systems offers an opportunity to investigate the outcomes of planet formation and evolution while controlling for initial conditions and environment. Those in resonance (with their orbital periods related by a ratio of small integers) are particularly valuable because they imply a system architecture practically unchanged since its birth. Here we present the observations of six transiting planets around the bright nearby star HD 110067. We find that the planets follow a chain of resonant orbits. A dynamical study of the innermost planet triplet allowed the prediction and later confirmation of the orbits of the rest of the planets in the system. The six planets are found to be sub-Neptunes with radii ranging from 1.94R⊕ to 2.85R⊕. Three of the planets have measured masses, yielding low bulk densities that suggest the presence of large hydrogen-dominated atmospheres.

Diagnostic accuracy of patch testing based in clinical response to contact allergen restrictions in allergic contact dermatitis.

Summary: Background. Patch testing (PT) is used to identify substances that cause allergic contact dermatitis (ACD). However, the clinical effects of allergen restrictions following PT have not been thoroughly investigated. This study aims to assess the diagnostic accuracy of PT in patients suspected of having ACD. Methods. Prospective study. PT were performed in patients with clinical diagnosis of ACD. Patients with a positive PT (case group) had a strict restriction of the suspected substance for one month. In patients with negative patch testing (control group), allergen restriction was based in clinical history. Clinical reduction (CR) of at least 50% in disease activity (CR50%) after one month of allergen restriction was considered clinically relevant. Total control was defined as clinical reduction of at least 90% (CR90%). Results. From 400 patients, 66.2% had a positive PT. The sensitivity of PT to identify CR50% was 84%, specificity 47%, PPV 53%, and NPV 81%. Only 10.5% of patients achieved CR90%. Conclusions. The PT had moderate diagnostic accuracy. It could be useful as a screening, but a positive result should be confirmed with controlled allergen restriction. The low number of patients who achieved a 90% CR invites to reconsider the allergens included in PT and the mechanistic processes of the disease.

Four-year Epidemiological Surveillance of the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy: Current Situation and Trends. / Vigilancia epidemiológica en los últimos 4 años del Registro Español de Investigación en Dermatitis de Contacto y Alergia Cutánea: situación actual y tendencias.

BACKGROUND: The epidemiological surveillance of contact dermatitis is one of the objectives of the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy. Knowing whether the prevalence of positive tests to the different allergens changes over time is important for this monitoring process. OBJECTIVES: To describe the various temporary trends in allergen positivity in the GEIDAC standard series from 2018 through December 31, 2022. METHODS: This was a multicenter, observational trial of consecutive patients analyzed via patch tests as part of the study of possible allergic contact dermatitises collected prospectively within the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy. The data was analyzed using 2 statistical tests: one homogeneity test (to describe the changes seen over time) and one trend test (to see whether the changes described followed a linear trend). RESULTS: A total of 11327 patients were included in the study. Overall, the allergens associated with a highest sensitization were nickel sulfate, methylisothiazolinone, cobalt chloride, methylchloroisothiazolinone/methylisothiazolinone, and fragrance mix i. A statistically significant decrease was found in the percentage of methylisothiazolinone positive tests across the study years with an orderly trend. CONCLUSIONS: Although various changes were seen in the sensitizations trends to several allergens of the standard testing, it became obvious that a high sensitization to nickel, methylchloroisothiazolinone/methylisothiazolinone and fragrances mix i remained. Only a significant downward trend was seen for methylisothiazolinone.

Evaluation of a school-based sun safety education program in Reunion Island, 2016-2017.

BACKGROUND: Sun exposure, especially during childhood, is the main environmental risk factor for skin cancers. This study evaluated the impact of the school-based sun safety education program "Living with the Sun" on the knowledge and behavior of primary school children regarding sun safety in Reunion Island. METHODS: This multicenter, comparative intervention study was conducted in selected primary schools of Reunion during the 2016-2017 school year. The intervention consisted of an in-class slide-show presentation on sun safety, a teaching guide, and school trips during which children were offered sunscreen and were requested to wear sunglasses, a T-shirt, and a cap. The children completed a questionnaire before and after the intervention. The percentage of children wearing a cap in school playgrounds at the end of the school year was compared between paired intervention and control schools. RESULTS: Seven hundred children from 7 Reunionese schools completed the questionnaire before and after the intervention. There was a statistically significant improvement in children's knowledge of sun safety, with differences between schools, teachers, school levels, and questionnaire responses. The percentage of children wearing a cap at the end of the school year was significantly higher in intervention schools compared to control schools. CONCLUSIONS: Children's knowledge and behavior regarding sun safety improved significantly as a result of the intervention.

Consensus on the Definition of Control and Remission in Chronic Urticaria.

The terms control and remission and other key terms used in chronic urticaria (CU) such as flare-up, relapse, exacerbation, and recurrence have not been fully defined in the literature. Disease monitoring and treatment goals in clinical practice are not well established. After a qualitative appraisal of available evidence, we aimed to find a consensus definition of control and remission, clarify key terminology, provide guidance on how to monitor the disease, and establish treatment goals in clinical practice. A modified Delphi consensus approach was used. Based on a literature review, a scientific committee provided 137 statements addressing controversial definitions and terms, available patient-reported outcomes (PROs), and recommendations on how to measure therapeutic objectives in CU. The questionnaire was evaluated by 138 expert allergists and dermatologists. A consensus was reached on 105 out of the 137 proposed items (76.6%). The experts agreed that complete control and remission of CU could be defined as the absence of signs or symptoms while on treatment and in the absence of treatment, respectively. Consensus was not reached on the definition of other key terms such as flare-up, exacerbation, and recurrence. The panel agreed that the objective of therapy in CU should be to achieve complete control. PROs that define the degree of control (complete, good, partial, or absence) were established. An algorithm for disease assessment is provided. In conclusion, this work offers consensus definitions and tools that may be useful in the management of patients with CU.

Daily Clinical Practice in the Management of Chronic Urticaria in Spain: Results of the UCREX Study.

BACKGROUND: Chronic Urticaria (CU) is a debilitating disease whose treatment is mainly symptomatic. UCREX study aimed to identify CU patients' profile, disease management and quality-of-life (QoL) in daily clinical practice in Spain. METHODS: Observational, 12-months prospective, multicenter study, included de novo or established CU patients attending to dermatology/allergy consultations in 39 Spanish hospitals. MAIN VARIABLES: Urticaria Activity Score (UAS), UAS over 7 days (UAS7). Secondary variables: CU-QoL Questionnaire (CU-Q2oL), EuroQol-5 dimensions (EQ-5D), Medical Outcomes Study Sleep (MOS-Sleep) scale, Hospital Anxiety and Depression Scale (HADS). RESULTS: 361 patients included. Of them, 176 (48.8%) considered for the main objective analysis. Mean age (SD) of 46.6 (14.2) years and 71.8% women. The year prior to inclusion, most patients (57.1%) were treated with non-sedating H1-antihistamines (NS-H1AH). At baseline, mean (SD) 3.6 (6.8) visits were registered to primary care. Mean (SD) UAS7 at baseline was 14.3 (11.0) and CU-Q2oL 24.1 (17.0) which tended to improve by 8.6 (9.7) and 13.9 (15.0), respectively, at 12-months. MOS-Sleep and EQ-5D remained steady during the study, except pain/discomfort and anxiety/depression which went from 58.7% and 49.6% to 29.6% and 26.9%, respectively. At baseline, HADS showed a mean (SD) anxiety of 8.7 (4.5) and depression 5.1 (4.4), decreasing to 7.0 (4.3) and 4.7 (4.3), respectively, at 12-months. CONCLUSIONS: Although most CU patients are treated with NS-H1AH, disease activity is still important, negatively affecting patients' QoL, work activity and healthcare resources use. An appropriate disease management could be the basis for symptoms control, QoL improvement and resources optimization.

Daily Clinical Practice in the Management of Chronic Urticaria in Spain: Results of the UCREX Study. / [Artículo traducido] Práctica clínica diaria en el manejo de la urticaria crónica en España: resultados del estudio UCREX.

BACKGROUND: Chronic Urticaria (CU) is a debilitating disease whose treatment is mainly symptomatic. UCREX study aimed to identify CU patients' profile, disease management and quality-of-life (QoL) in daily clinical practice in Spain. METHODS: Observational, 12-months prospective, multicenter study, included de novo or established CU patients attending to dermatology/allergy consultations in 39 Spanish hospitals. MAIN VARIABLES: Urticaria Activity Score (UAS), UAS over 7 days (UAS7). Secondary variables: CU-QoL Questionnaire (CU-Q2oL), EuroQol-5 dimensions (EQ-5D), Medical Outcomes Study Sleep (MOS-Sleep) scale, Hospital Anxiety and Depression Scale (HADS). RESULTS: 361 patients included. Of them, 176 (48.8%) considered for the main objective analysis. Mean age (SD) of 46.6 (14.2) years and 71.8% women. The year prior to inclusion, most patients (57.1%) were treated with non-sedating H1-antihistamines (NS-H1AH). At baseline, mean (SD) 3.6 (6.8) visits were registered to primary care. Mean (SD) UAS7 at baseline was 14.3 (11.0) and CU-Q2oL 24.1 (17.0) which tended to improve by 8.6 (9.7) and 13.9 (15.0), respectively, at 12-months. MOS-Sleep and EQ-5D remained steady during the study, except pain/discomfort and anxiety/depression which went from 58.7% and 49.6% to 29.6% and 26.9%, respectively. At baseline, HADS showed a mean (SD) anxiety of 8.7 (4.5) and depression 5.1 (4.4), decreasing to 7.0 (4.3) and 4.7 (4.3), respectively, at 12-months. CONCLUSIONS: Although most CU patients are treated with NS-H1AH, disease activity is still important, negatively affecting patients' QoL, work activity and healthcare resources use. An appropriate disease management could be the basis for symptoms control, QoL improvement and resources optimization.

Ivermectin safety in infants and children under 15 kg treated for scabies: a multicentric observational study.

BACKGROUND: Scabies is a frequent condition seen in infants and children. Only topical treatments have been approved in infants, but some of them are poorly tolerated. Oral ivermectin is approved for the treatment of scabies in several countries, but its use in infants and children weighing < 15 kg is off label. OBJECTIVES: To assess the safety of ivermectin in infants and young children, and to collect data on ivermectin efficacy in these age groups. METHODS: This study was performed in the dermatology and paediatric dermatology departments of 28 French centres between July 2012 and November 2015. Physicians treating an infant or child weighing < 15 kg for scabies with oral ivermectin were asked to send back a completed standardized and anonymous questionnaire, and the data were analysed. RESULTS: Data were collected on 170 infants and children aged 1-64 months, with a body weight of 4-14·5 kg, who were treated with oral ivermectin. The mean dose received was 223 µg kg-1 and 89% of the patients received a systematic second dose. Concomitant topical treatment was administered to 73% of patients. Adverse events were reported in seven patients (4%) and were not severe. At the follow-up visit, 139 (85%) patients had achieved healing. Factors significantly associated with healing were an ivermectin dose > 200 µg kg-1 (P < 0·001), and a delay between those two doses of < 10 days (P = 0·025). CONCLUSIONS: Our findings suggest the safety and efficacy of ivermectin for the treatment of scabies in infants and young children. What's already known about this topic? Scabies is a frequent condition in small children and infants, but the therapeutic options are limited. Ivermectin has been approved for the treatment of scabies in adults and children > 15 kg, but its use is off-label in infants and children weighing < 15 kg. Safety data on the use of ivermectin in children weighing < 15 kg are limited. What does this study add? Of 170 infants and children weighing < 15 kg who were treated for scabies with oral ivermectin, there were only seven reported mild adverse events and no serious ones. Our results show that ivermectin is effective in treating scabies in 85% of patients. Efficacy is higher when the received dose exceeds 200 µg kg-1 and when the delay between the two doses is < 10 days. Respond to this article.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients.

BACKGROUND: Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification. OBJECTIVES: To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations. METHODS: We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined. CONCLUSIONS: A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

Dermatological manifestations in Noonan syndrome: a prospective multicentric study of 129 patients positive for mutation.

BACKGROUND: Data on dermatological manifestations of Noonan syndrome (NS) remain heterogeneous and are based on limited dermatological expertise. OBJECTIVES: To describe the dermatological manifestations of NS, compare them with the literature findings, and test for dermatological phenotype-genotype correlations with or without the presence of PTPN11 mutations. METHODS: We performed a large 4-year, prospective, multicentric, collaborative dermatological and genetic study. RESULTS: Overall, 129 patients with NS were enrolled, including 65 patients with PTPN11-NS, 34 patients with PTPN11-NS with multiple lentigines (NSML), and 30 patients with NS who had a mutation other than PTPN11. Easy bruising was the most frequent dermatological finding in PTPN11-NS, present in 53·8% of patients. Multiple lentigines and café-au-lait macules (n ≥ 3) were present in 94% and 80% of cases of NSML linked to specific mutations of PTPN11, respectively. Atypical forms of NSML could be associated with NS with RAF1 or NRAS mutations. In univariate analysis, patients without a PTPN11 mutation showed (i) a significantly higher frequency of keratinization disorders (P = 0·001), including keratosis pilaris (P = 0·005), ulerythema ophryogenes (P = 0·0001) and palmar and/or plantar hyperkeratosis (P = 0·06, trend association), and (ii) a significantly higher frequency of scarce scalp hair (P = 0·035) and scarce or absent eyelashes (P = 0·06, trend association) than those with PTPN11 mutations. CONCLUSIONS: The cutaneous phenotype of NS with a PTPN11 mutation is generally mild and nonspecific, whereas the absence of a PTPN11 mutation is associated with a high frequency of keratinization disorders and hair abnormalities.

Dual MET and ERBB inhibition overcomes intratumor plasticity in osimertinib-resistant-advanced non-small-cell lung cancer (NSCLC).

BACKGROUND: Third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as osimertinib are the last line of targeted treatment of metastatic non-small-cell lung cancer (NSCLC) EGFR-mutant harboring T790M. Different mechanisms of acquired resistance to third-generation EGFR-TKIs have been proposed. It is therefore crucial to identify new and effective strategies to overcome successive acquired mechanisms of resistance. METHODS: For Amplicon-seq analysis, samples from the index patient (primary and metastasis lesions at different timepoints) as well as the patient-derived orthotopic xenograft tumors corresponding to the different treatment arms were used. All samples were formalin-fixed paraffin-embedded, selected and evaluated by a pathologist. For droplet digital PCR, 20 patients diagnosed with NSCLC at baseline or progression to different lines of TKI therapies were selected. Formalin-fixed paraffin-embedded blocks corresponding to either primary tumor or metastasis specimens were used for analysis. For single-cell analysis, orthotopically grown metastases were dissected from the brain of an athymic nu/nu mouse and cryopreserved at -80°C. RESULTS: In a brain metastasis lesion from a NSCLC patient presenting an EGFR T790M mutation, we detected MET gene amplification after prolonged treatment with osimertinib. Importantly, the combination of capmatinib (c-MET inhibitor) and afatinib (ErbB-1/2/4 inhibitor) completely suppressed tumor growth in mice orthotopically injected with cells derived from this brain metastasis. In those mice treated with capmatinib or afatinib as monotherapy, we observed the emergence of KRAS G12C clones. Single-cell gene expression analyses also revealed intratumor heterogeneity, indicating the presence of a KRAS-driven subclone. We also detected low-frequent KRAS G12C alleles in patients treated with various EGFR-TKIs. CONCLUSION: Acquired resistance to subsequent EGFR-TKI treatment lines in EGFR-mutant lung cancer patients may induce genetic plasticity. We assess the biological insights of tumor heterogeneity in an osimertinib-resistant tumor with acquired MET-amplification and propose new treatment strategies in this situation.

[Impact of sex and age on the clinical and epidemiological aspects of childhood psoriasis: Data from a French cross-sectional multicentre study]. / Impact de l'âge et du sexe sur les aspects cliniques et épidémiologiques du psoriasis de l'enfant. Données d'une étude transversale multicentrique française.

BACKGROUND: The prevalence of childhood psoriasis is estimated at between 0.4% and 0.7%. Clinical aspects of the diseases depend on age. The aim of this study was to investigate the clinical aspects of psoriasis according to age and sex. PATIENTS AND METHODS: A cross-sectional, multicentre study of children with psoriasis was performed by investigators belonging to the Research Group of the French Society of Paediatric Dermatology. The study was conducted from April 2012 to March 2013. Inclusion criteria were age less than 18 years and clinical diagnosis of psoriasis. The children were classified into 3 groups by age: infants: <2 years; children: ≥2 years and <13 years; adolescents≥13 years. The information collected included demographic data, clinical, epidemiological, and therapeutic aspects of the psoriasis, as well as analysis of comorbidities. RESULTS: Three hundred and thirteen children were included: 27 (8.6%) infants, 207 (66.1%) children, and 79 (25.2%) adolescents. Plaque psoriasis was the most frequent clinical type of psoriasis seen in children and adolescents (>41%), but it accounted for only 25.9% of psoriasis of infants (P<0.0001). Napkin psoriasis (37.0%) and inverse psoriasis (22.2%) were the most common forms of psoriasis seen in infants and were described significantly more frequently in this group than in the two other groups (P<0.003). Nail involvement was more common in adolescents (37.2%, P=0.03) and children (32.9%) than in infants (14.8%) and affected boys more than girls (43.6% vs 22.0%, P<0.0001). Girls presented scalp psoriasis more frequently (17.7% vs 8.7%, P=0.02). Local vitamin-D treatment and systemic therapies were used more frequently in children and adolescents than in infants. There was no significant difference for treatment use, including for acitretin, according to gender. DISCUSSION: Plaque psoriasis was the most common clinical type of psoriasis in children but affected less than 50% of the children. Age had a significant impact on extra-cutaneous skin disorders and on treatment used, while sex had little incidence. The frequency of comorbidities was not affected by age. CONCLUSION: Childhood psoriasis thus presents specific characteristics dependent on the age of the child. The results of studies exclusively dealing with adults cannot be extrapolated to children.

Psoriasis and obesity in French children: a case-control, multicentre study.

BACKGROUND: Obesity is more common in adults with psoriasis than in the general population, but there is a lack of data available regarding this association in children. OBJECTIVES: To evaluate whether obesity was more common in French children with psoriasis of any clinical type or severity. METHODS: A multicentre case-control study was performed in 23 French dermatology centres. Children without chronic or genetic inflammatory disease were selected as controls and matched for age, sex and dermatology centre. We used three weight cut-off categories to compare the two groups: overweight, overweight with abdominal obesity and overweight with obesity according to the French Health Authority guidelines. RESULTS: A total of 261 children with psoriasis were included. The mean age was 9.8 years, 126 were boys and 135 were girls. Overall, 42.5% of these children had plaque psoriasis and 32.2% had severe psoriasis. There was no difference between the psoriasis and control groups when the frequency of children who were overweight was compared (20·7% in psoriasis group vs. 17·1% in control group; P = 0·18). Overweight with abdominal obesity including obesity (18·4% vs. 10·4%; P = 0·009) and obesity alone (10·0% vs. 3·1%; P = 0·001) were more common in the psoriasis group. CONCLUSIONS: This study shows that being overweight with abdominal obesity and being obese is more common in children with psoriasis than in controls. The risk factors are the same as those that affect the French general population, i.e. female sex and having a parent who was overweight. The severity and clinical type of psoriasis do not affect overweight and obesity.

Lymphomatoid papulosis in children: a series of 25 cases.

BACKGROUND: Lymphomatoid papulosis (LyP) is an uncommon cutaneous T-cell lymphoproliferative disorder (CTLPD) rarely encountered in children. OBJECTIVES: To specify characteristics of paediatric LyP and to describe both diagnostic difficulties and the course of the disease with the experience of 10 years' follow-up. METHODS: This was a retrospective, single-centre study of 25 children diagnosed with LyP according to the 2008 World Health Organization guidelines, and a clinical and pathological correlation by two experts. RESULTS: The mean age at onset was 7·5 years. The lesions were mostly papulonodular with frequent pruritus (40%). Mucosal involvement was sometimes observed. A single ulcerative nodule was initially suggestive of a primary cutaneous anaplastic large-cell lymphoma (C-ALCL). Pityriasis lichenoides was associated in 36% of cases, atopic dermatitis in 28% and nonspecific infections in 28%. Complete remission was observed in 44% of cases. Through the mean follow-up of 10 years, none of our patients have experienced lymphoma occurrence. Histopathological subtype A clearly predominated (82%). A marked eosinophilic infiltrate was present in 44% of cases and a cutaneous T-gamma clone in 40%. No correlation was observed between histopathological subtype, cutaneous clone or LyP clinical course. CONCLUSIONS: Paediatric LyP belongs to the group of CD30-positive CTLPDs including C-ALCL. Children have to be carefully followed up lifelong, even if the prognosis appears good. The high frequencies of an associated viral infection, atopic dermatitis, marked eosinophilic infiltrate and a good outcome suggest that paediatric LyP could be considered a reactional disease rather than a malignant disorder.

Aplasia cutis congenita with dystrophic epidermolysis bullosa: clinical and mutational study.

BACKGROUND: Aplasia cutis congenita (ACC) has been associated with all clinical forms of inherited epidermolysis bullosa (EB), including dominant and recessive dystrophic EB (DDEB and RDEB). To date, only a few patients with DEB specifically combined with ACC have been described and genotyped and almost all cases represent dominant forms of the condition. OBJECTIVES: The aim of this study was to describe new mutations of COL7A1 in patients with DEB and ACC and investigate possible genotype-phenotype correlations. METHODS: Twenty-two patients with DEB and ACC were included among the 123 patients with DEB whose COL7A1 mutations have been identified in the Reference Centre in Nice. RESULTS: Seven patients presented a severe generalized RDEB phenotype (RDEB-sev-gen), while the other 15 suffered from milder phenotypes. We identified 28 mutations in COL7A1, of which nine are novel. Patients with severe phenotypes have mostly mutations leading to premature termination codon (PTC) and/or splice-site or missense mutations. Patients with the milder phenotypes have mostly glycine or arginine substitutions associated or not with other types of mutations. All amino acid substitutions fell within the carboxyl portion of the triple helix domain (THD) of collagen VII, close to the THD interruptions. CONCLUSIONS: Our findings suggest that ACC is a frequent manifestation in patients with DEB irrespective of the severity of the disease, and is due to leg rubbing in utero. In children with a moderate form of DEB with no or moderate skin fragility, a glycine substitution near the THD interruption domain of the collagen VII leading to thermolabile protein could explain this phenomenon.

Hydrogen-bonded assemblies of iron(II) spin crossover complexes.

The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)2]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4'-dicarboxylate (BPDC). Compound [Fe(bpp)2](ADC)·9H2O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2](HBTC)·5H2O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2](BPDC)·5H2O (3) has a ground HS state in its fully hydrated form.