"An unprecedented occurrence: a case report of pulmonary hypertension manifestation in Donohue syndrome"

INTRODUCTION

Donohue syndrome (DS), also referred to as leprechaunism, is a remarkably uncommon autosomal recessive disorder that primarily affects the endocrine system. Its incidence rate is exceedingly low, with only 1 case reported per 4 million live births. The syndrome is distinguished by a series of characteristic clinical features.

CASE PRESENTATION

We present a case of a twenty-month-old male with DS who experienced a range of dysmorphic and clinical features with the involvement of multiple systems. These features include skin hyperpigmentation, hypertrichosis, distinct facial features, abdominal distension, and microcephaly, with the involvement of the endocrine, renal, respiratory, and cardiac systems.

CONCLUSION

The primary features of DS involve severe insulin resistance and growth abnormalities, the association with pulmonary hypertension (PHTN) has not been reported before. This finding adds more complexity to the condition. To the best of the author's knowledge, this is the first report for a patient with DS who has PHTN. Further investigation is required since the mechanisms behind the development of PHTN in DS are not entirely understood. Shedding light on this association will contribute to better management strategies and outcomes for affected patients.

Management challenges of Rabson Mendenhall syndrome in a resource limited country: a case report

OBJECTIVES

Rabson Mendenhall syndrome  (RMS) is a rare form of insulin resistance syndrome caused by insulin receptor mutation. In term of severity, it lies at an intermediate point on spectrum of insulin resistance with Donohue syndrome flanking the severe and Type A insulin resistance at the mild end. We are reporting a 3.5-month-old boy with RMS along with its management challenges in a resource limited country.

CASE PRESENTATION

An infant presented at 3.5-month of an age with failure to thrive and fluctuating blood glucose level (hyperglycaemia and hypoglycaemia) along with clinical features of insulin resistance. He was found to have raised HbA1C, high insulin and C peptide level and a homozygous mutation in INSR gene c.1049C>T, (p.Ser350 Leu) confirming the diagnosis of RMS. He was managed with long-acting insulin (Detemir) along with frequent feeding.

CONCLUSIONS

RMS in resource limited countries could be managed with frequent feeding along with insulin. Early diagnosis and management can improve long term outcome.

Clinical and Functional Characterization of Novel INSR Variants in Two Families With Severe Insulin Resistance Syndrome

OBJECTIVE

Defects in the insulin receptor (INSR) gene cause various severe insulin resistance conditions, including Donohue syndrome (DS), Rabson-Mendenhall syndrome (RMS) and type A insulin resistance (type A-IR). This study aimed to investigate the clinical characterization and molecular defects in three Chinese children with INSR-related insulin resistance syndrome.

METHODS

We reviewed the clinical data of three Chinese children with INSR-related insulin resistance syndrome from two unrelated kindreds. Genetic analysis was performed using whole-exome sequencing and the effects of the novel variants were further assessed by in vitro functional assays.

RESULTS

The proband with type A-IR presented with acanthosis nigricans, hypertrichosis, and euglycemia with mild insulin resistance in early childhood. His sister presented with features typical of type A-IR and was diagnosed with diabetes mellitus with severe insulin resistance at the age of 9.8 years. The proband with DS showed typical dysmorphic characteristics, severe intrauterine growth retardation, extreme insulin resistance, fasting hypoglycemia and postprandial hyperglycemia from birth. The heterozygote variants c.[3670G>A]; c.[3614C>T] were identified in both siblings with type A-IR; and c.[749_751del]; c.[3355C>T] in the patient with DS. In vitro studies showed that the novel variant c.749_751del [p.(Thr250del)] in the α-subunit, reduced expression of the mature INSR protein and severely impaired INSR function. In contrast, the novel variant c.3670G>A [p.(Val1224Met)] in the β-subunit had no effect on total protein expression and phosphorylation of INSR and Akt, suggesting that the variant p.Val1224Met appeared to be tolerated and was not responsible for the severe insulin resistance.

CONCLUSION

Our study detailed the clinical features of three patients with type A-IR and DS, and identified two novel variants in the INSR gene. Functional assays indicated the novel variant p.Thr250del was pathogenic. In contrast, the novel variant p.Val1224Met was suggested to be tolerated by our experimental data, even though bioinformatics analyses predicted the variant as deleterious.

Intrauterine Growth Restriction and Hypertrophic Cardiomyopathy as Prenatal Ultrasound Findings in a Case of Leprechaunism

Donohue syndrome (leprechaunism; OMIM *246200) is a rare and often lethal autosomal recessive disease caused by mutations in the INSR gene. We report the case of a 29-year-old pregnant woman, primigravida, who was referred at 33 weeks of gestation for severe intrauterine growth restriction (IUGR). Ultrasound examination found severe IUGR associated with an obstructive hypertrophic cardiomyopathy (HCM), confirmed postnatally. The newborn's blood glucose level fluctuated from fasting hypoglycemia to postprandial hyperglycemia. The infant was found to be homozygous for a novel missense pathogenic variant, c.632C>T (p.T211l), in exon 2 of the INSR gene, predicted to result in an abnormal insulin receptor. To our knowledge, this is the first report of leprechaunism being revealed by IUGR and HCM during the prenatal period. Clinicians should keep in mind that the association of these prenatal signs could indicate leprechaunism and specific early neonatal management could be proposed, in particular with recombinant human insulin-like growth factor-I.

Ultra-rapid emergency genomic diagnosis of Donahue syndrome in a preterm infant within 17 hours

Genetic diseases are a major cause of neonatal morbidity and mortality. The clinical differential diagnosis in severely ill neonates, especially in premature infants, is challenging. Next generation sequencing (NGS) diagnostics is a valuable tool, but the turnaround time is often too long to provide a diagnosis in the time needed for clinical guidance in newborn intensive care units (NICU). To minimize turnaround time, we developed an ultra-rapid whole genome sequencing pipeline and tested it in clinical practice. Our pilot case, was a preterm infant presenting with several crises of dehydration, hypoglycaemia and hyponatremia together with nephrocalcinosis and hypertrophic cardiomyopathy. Whole genome sequencing was performed using a paired-end 2x75bp protocol. Sequencing data were exported after 50 sequencing cycles for a first analysis. After run completion, the rapid-sequencing protocol, a second analysis of the 2 x 75 paired-end run was performed. Both analyses comprised read-mapping and SNP-/indel calling on an on-site Edico Genome DRAGEN server, followed by functional annotation and pathogenicity prediction using in-house scripts. After the first analysis within 17 h, the emergency ultra-rapid protocol identified two novel compound heterozygous variants in the insulin receptor gene (INSR), pathogenic variants in which cause Donohue Syndrome. The genetic diagnosis could be confirmed by detection of hyperinsulinism and patient care adjusted. Nonetheless, we decided to pursue RNA studies, proving the functional effect of the novel splice variant and reduced expression levels of INSR in patients skin fibroblasts.

Two Novel Variants and One Previously Reported Variant in the Insulin Receptor Gene in Two Cases with Severe Insulin Resistance Syndrome

Donohue syndrome (DS) and Rabson-Mendenhall syndrome (RMS) are rare diseases caused by biallelic variants within the insulin receptor gene (INSR). Here, we report 2 cases: one with DS and the other with RMS. The case with DS presented with intrauterine growth retardation, nipple hypertrophy, clitoromegaly, distended abdomen, hypertrichosis, and dysmorphic features. The second case showed severe acanthosis nigricans, hyperkeratosis, and hypertrichosis. In both cases, abnormal glucose homeostasis due to severe insulin resistance was observed. The diagnosis of DS and RMS was established based on clinical characteristics, abnormal glucose homeostasis, high serum insulin levels, and determination of pathogenic variants in the INSR gene. The first case with DS has 2 novel homozygous variants, NM_000208.3, c.3122delA (p.N1041Mfs*16) and c.3419C>G (p.A1140G), and the second case with RMS has a previously reported homozygous variant NM_000208.3, c.3529+5G>A (IVS19+5G>A) in the INSR gene.

Evaluation of anti-insulin receptor antibodies as potential novel therapies for human insulin receptoropathy using cell culture models

AIMS/HYPOTHESIS

Bi-allelic loss-of-function mutations in the INSR gene (encoding the insulin receptor [INSR]) commonly cause extreme insulin resistance and early mortality. Therapeutic options are limited, but anti-INSR antibodies have been shown to activate two mutant receptors, S323L and F382V. This study evaluates four well-characterised murine anti-INSR monoclonal antibodies recognising distinct epitopes (83-7, 83-14, 18-44, 18-146) as surrogate agonists for potential targeted treatment of severe insulin resistance arising from insulin receptoropathies.

METHODS

Ten naturally occurring mutant human INSRs with defects affecting different aspects of receptor function were modelled and assessed for response to insulin and anti-INSR antibodies. A novel 3T3-L1 adipocyte model of insulin receptoropathy was generated, permitting conditional knockdown of endogenous mouse Insr by lentiviral expression of species-specific short hairpin (sh)RNAs with simultaneous expression of human mutant INSR transgenes.

RESULTS

All expressed mutant INSR bound to all antibodies tested. Eight mutants showed antibody-induced autophosphorylation, while co-treatment with antibody and insulin increased maximal phosphorylation compared with insulin alone. After knockdown of mouse Insr and expression of mutant INSR in 3T3-L1 adipocytes, two antibodies (83-7 and 83-14) activated signalling via protein kinase B (Akt) preferentially over signalling via extracellular signal-regulated kinase 1/2 (ERK1/2) for seven mutants. These antibodies stimulated glucose uptake via P193L, S323L, F382V and D707A mutant INSRs, with antibody response greater than insulin response for D707A.

CONCLUSIONS/INTERPRETATION

Anti-INSR monoclonal antibodies can activate selected naturally occurring mutant human insulin receptors, bringing closer the prospect of novel therapy for severe insulin resistance caused by recessive mutations.

Enteroinsular hormones in two siblings with Donohue syndrome and complete leptin deficiency

The main biochemical hallmark of the rare and lethal condition of Donohue syndrome (DS) is hyperinsulinemia. The roles of the gut and other pancreatic hormones involved in glucose metabolism, satiety and energy expenditure have not been previously reported in DS. Two siblings with genetically confirmed DS and extremely low weight underwent a mixed meal (MM) test where pancreatic hormones insulin, C-peptide, glucagon, active amylin, pancreatic polypeptide (PP) as well as gut hormones active glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), ghrelin, peptide YY (PYY) and leptin were analyzed using a Multiplex assay. Results were compared to those of 2 pediatric controls. As expected, concentrations of insulin, C-peptide and amylin were very high in DS cases. The serum glucagon concentration was undetectable at the time of hypoglycemia. GIPs concentrations were lower in the DS, however, this was not mimicked by the other incretin, GLP-1. Ghrelin concentrations were mainly undetectable (<13.7 pg/mL) in all participants. DS cases had higher PYY and dampened PP concentrations. Leptin levels remained completely undetectable (<137.0 pg/mL). Patients with DS have extremely high amylin levels, completely undetectable serum glucagon and leptin levels with abnormal satiety regulating hormone PP with a relatively normal ghrelin response during a MM test. The low serum GIP might be acting as physiological brake on insulin secretion. The undetectable serum leptin levels suggest the potential of using leptin analogues as therapy for DS patients.

Mecasermin in Insulin Receptor-Related Severe Insulin Resistance Syndromes: Case Report and Review of the Literature

Mutations in the insulin receptor (INSR) gene underlie rare severe INSR-related insulin resistance syndromes (SIR), including insulin resistance type A, Rabson–Mendenhall syndrome and Donohue syndrome (DS), with DS representing the most severe form of insulin resistance. Treatment of these cases is challenging, with the majority of DS patients dying within the first two years of life. rhIGF-I (mecasermin) has been reported to improve metabolic control and increase lifespan in DS patients. A case report and literature review were completed. We present a case involving a male patient with DS, harbouring a homozygous mutation in the INSR gene (c.591delC). Initial rhIGF-I application via BID (twice daily) injection was unsatisfactory, but continuous subcutaneous rhIGF-I infusion via an insulin pump improved weight development and diabetes control (HbA1c decreased from 10 to 7.6%). However, our patient died at 22 months of age during the course of a respiratory infection in in Libya. Currently available data in the literature comprising more than 30 treated patients worldwide seem to support a trial of rhIGF-I in SIR. rhIGF-I represents a treatment option for challenging SIR cases, but careful consideration of the therapeutic benefits and the burden of the disease is warranted. Continuous application via pump might be advantageous compared to single injections.

Donohue syndrome: A review of literature, case series, and anesthetic considerations

BACKGROUND

Donohue syndrome is a rare autosomal recessive disorder of insulin resistance, causing a functional defect in insulin receptor function, and affecting the ability of the insulin to bind the receptor. Features include severe hyperinsulinism and fasting hypoglycemia, along with severe failure to thrive despite feeding. An accelerated fasting state results in muscle wasting, decreased subcutaneous fat, and an excess of thick skin. A reduced thoracic diameter is accentuated by increased abdominal distension, which impacts on respiratory reserve. Cardiac disease develops early in life, with progressive hypertrophic cardiomyopathy as a result of hyperinsulinism. Prognosis is poor with the majority of patients dying in infancy of sepsis. The aim of this review is to report our experience of providing anesthesia for patients with Donohue syndrome, and inform guidance for safe management of these children, based on a comprehensive literature review.

METHODS

A literature search was carried out using PubMed, Medline, and the Cochrane Library, and using the MESH search terms detailed below. Patients were identified by formal request to the department of pediatric endocrinology at Great Ormond Street Hospital. Each patient's notes were searched manually and electronically for both clinical presentation and outcome, and anesthesia records.

DISCUSSION

There is currently no published literature relating to anesthetic management of Donohue syndrome. We report a case series of 5 patients with Donohue syndrome who have presented to our institution. This small series of children with this complex disorder demonstrates a clearly increased risk of general anesthesia. Many of the risks relate to restrictive lung disease and abdominal distension which worsens with bag valve mask ventilation and limited respiratory reserve which leads to precipitous desaturation. During induction, a spontaneously breathing technique is recommended. If required, bag valve mask ventilation should be accompanied by constant gastric aspiration. Intubation is challenging, and a difficult airway plan, including a second experienced anesthetist and ENT support, should be in place. These children are predisposed to developing cardiomyopathy and therefore at risk of cardiovascular collapse under anesthesia.

A case of Donohue syndrome "Leprechaunism" with a novel mutation in the insulin receptor gene

Donohue syndrome (Leprechaunism) is characterized by severe insulin resistance, hyperinsulinemia, postprandial hyperglycemia, preprandial hypoglycemia, intrauterine and postnatal growth retardation, dysmorphic findings, and clinical and laboratory findings of hyperandrogenemia due to homozygous or compound heterozygous inactivating mutations in the insulin receptor gene. A female newborn presented with lack of subcutaneous fat tissue, bilateral simian creases, hypertrichosis, especially on her face, gingival hypertrophy, cliteromegaly, and prominent nipples. Her laboratory tests revealed hyperandrogenism, postprandial hyperglycemia and preprandial hypoglycemia, and very high concurrent insulin levels. She was diagnosed as having Donohue syndrome. Metformin and continuous nasogastric feeding were administrated. During follow-up, relatively good glycemic control was obtained. However, severe hypertrophic obstructive cardiomyopathy and severe malnutrition developed. She died aged 75 days of severe heart failure and pneumonia. Her insulin receptors gene analysis revealed a compound heterozygous mutation. One of these mutations was a p.R813 (c.2437C>T) mutation, which was defined previously and shown also in her father, the other mutation was a novel p.777-790delVAAFPNTSSTSVPT mutation, also shown in her mother. The parents were heterozygous for these mutations.

Hypertrophic cardiomyopathy in Donohue syndrome

We report the case of a patient with Donohue syndrome who died of heart failure due to obstructive hypertrophic cardiomyopathy. A literature survey revealed that hypertrophic cardiomyopathy was present in 30% of these patients and was often fatal. Therefore, every patient with Donohue syndrome should be screened for hypertrophic cardiomyopathy.

First molecular diagnosis of Donohue syndrome in Africa: novel unusual insertion/deletion mutation in the INSR gene

Donohue syndrome (DS) is a very rare autosomal recessive disease affecting less than one in a million life births. It represents the most severe form of insulin resistance due to mutations involving the insulin receptor (IR) gene "INSR". DS is characterized by pre- and postnatal growth retardation with failure-to-thrive, lipoatrophy, acanthosis nigricans, hypertrichosis, and dysmorphic features. An exhaustive INSR gene sequencing was performed after PCR amplification of coding exons and introns boundaries. Bioinformatic tools, including ESEfinder, MFOLD and Proter software were also used to predict the impact of INSR mutation on INSR on gene expression as well as on the protein structure and function. The results have shown a novel unusual c.3003_3012delinsGGAAG (p.S1001_D1004delinsRE) insertion/deletion (indel) mutation within the exon 16 in the three patients, which represent the fourth indel mutation within the INSR gene. The mutation modifies the secondary structure of DNA and RNA, as well as the composition of exonic splicing enhancers of exon 16. Moreover, despite the conservation of the secondary structure of the IR, the p.S1001_D1004delinsRE in-frame mutation is accompanied by the loss of four amino acids replaced by two residues of different nature and hydrophobicity level in the juxtamembrane domain of the receptor. The results have confirmed the role of the juxtamembrane domain of IR involved in a crucial interaction of the IR with cellular effectors essentially the IR substrate 1 (IRS-1), the SHC and the Nck proteins that ensure the signal mediated by the insulin transduction pathway in target cells. Our findings have also proven the genotype/phenotype correlation between INSR mutation and DS phenotype severity.

Insulin Receptor and the Kidney: Nephrocalcinosis in Patients with Recessive INSR Mutations

BACKGROUND/AIMS

Donohue and Rabson-Mendenhall syndrome are rare autosomal recessive disorders caused by mutations in the insulin receptor gene, INSR. Phenotypic features include extreme insulin resistance, linear growth retardation, paucity of fat and muscle, and soft tissue overgrowth. The insulin receptor is also expressed in the kidney, where animal data suggest it plays a role in glomerular function and blood pressure (BP) regulation, yet such a role in the human kidney is untested. Patients with biallelic INSR mutations provide a rare opportunity to ascertain its role in man.

METHODS

Retrospective review of patients with INSR mutations. Data for BP, renal imaging, plasma creatinine and electrolyte levels, as well as urine protein, albumin and calcium excretion were sought from the treating clinicians.

RESULTS

From 33 patients with INSR mutations, data were available for 17 patients. Plasma creatinine was low (mean ± SD: 25 ± 9 μmol/l) and mean plasma electrolyte concentrations were within the normal range (n = 13). Systolic BP ranged between the 18th and 91st percentile for age, sex, height and weight (n = 9; mean ± SD: 49 ± 24). Twenty-four-hour urinary calcium data were available from 10 patients and revealed hypercalciuria in all (mean ± SD: 0.32 ± 0.17 mmol/kg/day; normal <0.1). Nephrocalcinosis was present in all patients (n = 17). Urinary albumin excretion (n = 7) ranged from 4.3-122.5 μg/min (mean ± SD: 32.4 ± 41.0 μg/min; normal <20).

CONCLUSIONS

INSR dysfunction is associated with hypercalciuria and nephrocalcinosis. No other consistent abnormality of renal function was noted. Normotension and stable glomerular function with only moderate proteinuria is in contrast to genetically modified mice who have elevated BP and progressive diabetic nephropathy.

Sequencing analysis of insulin receptor defects and detection of two novel mutations in INSR gene

Mutations in the insulin receptor gene cause the inherited insulin resistant syndromes Leprechaunism and Rabson–Mendenhall syndrome. These recessive conditions are characterized by intrauterine and post-natal growth restrictions, dysmorphic features, altered glucose homeostasis, and early demise. The insulin receptor gene (INSR) maps to the short arm of chromosome 19 and is composed of 22 exons. Here we optimize the conditions for sequencing this gene and report novel mutations in patients with severe insulin resistance.

Methods

PCR amplification of the 22 coding exons of the INSR gene was performed using M13-tailed primers. Bidirectional DNA sequencing was performed with BigDye Terminator chemistry and M13 primers and the product was analyzed on the ABI 3100 genetic analyzer. Data analysis was performed using Mutation Surveyor software comparing the sequence to a reference INSR sequence (Genbank NC_000019).

Results

We sequenced four patients with Leprechaunism or Rabson–Mendenhall syndromes as well as seven samples from normal individuals and confirmed previously identified mutations in the affected patients. Three of the four mutations identified in this group caused premature insertion of a stop codon. In addition, the INSR gene was sequenced in 14 clinical samples from patients with suspected insulin resistance and one novel mutation was found in an infant with a suspected diagnosis of Leprechaunism.

Discussion

Leprechaunism and Rabson–Mendenhall syndrome are very rare and difficult to diagnose. Diagnosis is currently based mostly on clinical criteria. Clinical availability of DNA sequencing can provide an objective way of confirming or excluding the diagnosis.

Two novel mutations identified in familial cases with Donohue syndrome

Donohue syndrome (DS) is a rare and lethal autosomal recessive disease caused by mutations in the insulin receptor (INSR) gene, manifesting marked insulin resistance, severe growth retardation, hypertrichosis, and characteristic dysmorphic features. We report the clinical, molecular, and biochemical characterization of three new patients with DS, and address genotype–phenotype issues playing a role in the pathophysiology of DS. A female infant born to first-degree cousins Muslim Arab parents and two brothers born to first-degree cousins Druze parents presented classical features of DS with hypertrophic cardiomyopathy and died in infancy. Each patient was found homozygous for one missense mutation within the extracellular domain of the INSR gene. Western blot analysis identified the proreceptor of INSR, but not its mature subunits alpha and beta. Of 95 healthy Muslims, no heterozygous was found and of 52 healthy Druze from the same village, one was heterozygous. This study presents two novel familial mutations in the alpha subunit of the INSR which appear to impair post-translational processing of the INSR, resulting loss of its function. Both mutations cause DS with hypertrophic cardiomyopathy and early death. Identification of the causative mutation enables prevention of this devastating disease.