Novel AVPR2 mutations and clinical characteristics in 28 Chinese families with congenital nephrogenic diabetes insipidus

AIMS

To investigate genotype and phenotype of congenital nephrogenic diabetes insipidus caused by AVPR2 mutations, which is rare and limitedly studied in Chinese population.

METHODS

88 subjects from 28 families with NDI in a department (Beijing, PUMCH) were screened for AVPR2 mutations. Medical records were retrospectively reviewed and characterized. Genotype and phenotype analysis was performed.

RESULTS

23 AVPR2 mutations were identified, including six novel mutations (p.Y117D, p.W208R, p.L313R, p.S127del, p.V162Sfs*30 and p.G251Pfs*96). The onset-age ranged from 1 week to 3 years. Common presentations were polydipsia and polyuria (100%) and intermittent fever (57%). 21% and 14% of patients had short stature and mental impairment. Urine SG and osmolality were decreased, while serum osmolality and sodium were high. Urological ultrasonography results showed hydronephrosis of the kidney (52%), dilation of the ureter (48%), and thickened bladder wall or increased residual urine (32%), led to intermittent urethral catheterization (7%), cystostomy (11%) and binary nephrostomy (4%). Urological defects were developed in older patients. Genotype and phenotype analysis revealed patients with non-missense mutations had higher levels of serum sodium than missense mutations.

CONCLUSION

In the first and largest case series of NDI caused by AVPR2 mutations in Chinese population, we established genetic profile and characterized clinical data, reporting six novel mutations. Further, we found genotype was associated with phenotype. This knowledge broadens genotype and phenotype spectrum of rare congenital NDI caused by AVPR2 mutations, and provides basis for studying molecular biology of AVPR2.

Deciphering the Role of Filamin B Calponin-Homology Domain in Causing the Larsen Syndrome, Boomerang Dysplasia, and Atelosteogenesis Type I Spectrum Disorders via a Computational Approach

Filamins (FLN) are a family of actin-binding proteins involved in regulating the cytoskeleton and signaling phenomenon by developing a network with F-actin and FLN-binding partners. The FLN family comprises three conserved isoforms in mammals: FLNA, FLNB, and FLNC. FLNB is a multidomain monomer protein with domains containing an actin-binding N-terminal domain (ABD 1-242), encompassing two calponin-homology domains (assigned CH1 and CH2). Primary variants in FLNB mostly occur in the domain (CH2) and surrounding the hinge-1 region. The four autosomal dominant disorders that are associated with FLNB variants are Larsen syndrome, atelosteogenesis type I (AOI), atelosteogenesis type III (AOIII), and boomerang dysplasia (BD). Despite the intense clustering of FLNB variants contributing to the LS-AO-BD disorders, the genotype-phenotype correlation is still enigmatic. In silico prediction tools and molecular dynamics simulation (MDS) approaches have offered the potential for variant classification and pathogenicity predictions. We retrieved 285 FLNB missense variants from the UniProt, ClinVar, and HGMD databases in the current study. Of these, five and 39 variants were located in the CH1 and CH2 domains, respectively. These variants were subjected to various pathogenicity and stability prediction tools, evolutionary and conservation analyses, and biophysical and physicochemical properties analyses. Molecular dynamics simulation (MDS) was performed on the three candidate variants in the CH2 domain (W148R, F161C, and L171R) that were predicted to be the most pathogenic. The MDS analysis results showed that these three variants are highly compact compared to the native protein, suggesting that they could affect the protein on the structural and functional levels. The computational approach demonstrates the differences between the FLNB mutants and the wild type in a structural and functional context. Our findings expand our knowledge on the genotype-phenotype correlation in FLNB-related LS-AO-BD disorders on the molecular level, which may pave the way for optimizing drug therapy by integrating precision medicine.

Etiology of severe short stature below -3 SDS in a screened Finnish population

OBJECTIVE

To describe the etiology of severe short stature in the Helsinki University Hospital district covering a population of 1.2 million that is subject to frequent growth monitoring and screening rules during childhood.

DESIGN

Retrospective cohort study.

METHODS

We identified all subjects born 1990 or later with a height SD score <-3, after the age of 3 years, from the Helsinki University Hospital district growth database. A total of 785 subjects (376 females and 409 males) fulfilled our inclusion criteria; we reviewed their medical records and growth data and report their underlying diagnoses.

RESULTS

A pathological cause for short stature was diagnosed in 76% of the girls and 71% of the boys (P = NS). Syndromes were the most numerous pathological cause (n = 160; 20%), followed by organ disorders (n = 127; 16%), growth hormone deficiency (GHD, n = 94; 12%), SGA without catch-up growth (n = 73; 9%), and skeletal dysplasias (n = 57; 7%). Idiopathic short stature (ISS) was diagnosed in 210 (27%) subjects. The probability of growth-related pathology, particularly of a syndrome or skeletal dysplasia, increased with the shorter height SD score and the greater deviation from the target height. Sitting height to height SDS was increased in subjects with ISS, GHD, and SGA (all P < 0.01).

CONCLUSIONS

Height <-3 SDS after 3 years of age usually results from a pathological cause and should be thoroughly investigated in specialized health care. The chance of finding a specific etiology increased with the severity of short stature, and the mismatch with target height.

Short stature in a boy with atypical progeria syndrome due to LMNA c.433G>A [p.(Glu145Lys)]: apparent growth hormone deficiency but poor response to growth hormone therapy

Background Hutchinson-Gilford progeria syndrome (HGPS) is a rare disease caused by pathogenic variants in the LMNA gene, which leads to premature aging. The median life expectancy is shortened to 13 years due to cardiovascular complications. Case report We present a boy born with a pathogenic LMNA variant c.433G > A, which causes atypical progeria syndrome (APS) and was previously described in one single patient. When investigated for poor growth prior to the diagnosis of APS, his laboratory tests revealed growth hormone (GH) deficiency and magnetic resonance imaging (MRI) of the midbrain showed partial empty sella. GH treatment had only a limited and transient effect. His first ischemic complication manifested at age 4.2 years; at the age of 7 years, he had a fatal haemorrhagic stroke. Conclusion To the best of our knowledge, this is the first patient with APS showing partial empty sella and GH deficiency that might have contributed to his poor growth. GH failed to improve long-term outcome.

Growth impairment in mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders that affect regulation of glycosaminoglycan (GAG) processing. In MPS, the lysosomes cannot efficiently break down GAGs, and the specific GAGs accumulated depend on the type of MPS. The level of impairment of breakdown varies between patients, making this one of the many factors that lead to a range of clinical presentations even in the same type of MPS. These clinical presentations usually involve skeletal dysplasia, in which the most common feature is bone growth impairment and successive short stature. Growth impairment occurs due to the deposition and retention of GAGs in bone and cartilage. The accumulation of GAGs in these tissues leads to progressive damage in cartilage that in turn reduces bone growth by destruction of the growth plate, incomplete ossification, and imbalance of growth. Imbalance of growth leads to various skeletal abnormalities including disproportionate dwarfism with short neck and trunk, prominent forehead, rigidity of joints, tracheal obstruction, kyphoscoliosis, pectus carinatum, platyspondyly, round-shaped vertebral bodies or beaking sign, underdeveloped acetabula, wide flared iliac, coxa valgus, flattered capital femoral epiphyses, and genu valgum. If left untreated, skeletal abnormalities including growth impairment result in a significant impact on these patients' quality of life and activity of daily living, leading to high morbidity and severe handicap. This review focuses on growth impairment in untreated patients with MPS. We comprehensively describe the growth abnormalities through height, weight, growth velocity, and BMI in each type of MPS and compare the status of growth with healthy age-matched controls. The timing, the degree, and the difference in growth impairment of each MPS are highlighted to understand the natural course of growth and to evaluate future therapeutic efficacy.

[Turner syndrome in the hôpital du Mali, a case]

Turner syndrome is a chromosomal aberration linked to the complete or partial absence of an X chromosome. Its prevalence is 1/2500 female newborns. We report a case in the department of internal medicine and endocrinology of the hospital of MALI. This was a 14-year old girl who consulted for stunting and puberty. She presented clinically a dysmorphic syndrome, TANNER stage1 secondary sexual characteristics, weight and height at -3 DS and a bone age estimated to 9½ years old on the X-ray of the hand. The hormonal assessment showed an elevation of FSH and LH and the genetic study showed an iso chromosome Xq. This result was part of a Turner syndrome with Xq iso chromosome.

Mutations in TKT Are the Cause of a Syndrome Including Short Stature, Developmental Delay, and Congenital Heart Defects

Whole-exome sequencing (WES) is increasingly being utilized to diagnose individuals with undiagnosed disorders. Developmental delay and short stature are common clinical indications for WES. We performed WES in three families, using proband-parent trios and two additional affected siblings. We identified a syndrome due to an autosomal-recessively inherited deficiency of transketolase, encoded by TKT, on chromosome 3p21. Our series includes three families with a total of five affected individuals, ranging in age from 4 to 25 years. Two families of Ashkenazi Jewish ancestry were homozygous for an 18 base pair in-frame insertion in TKT. The third family was compound heterozygous for nonsense and missense variants in TKT. All affected individuals had short stature and were developmentally delayed. Congenital heart defects were noted in four of the five affected individuals, and there was a history of chronic diarrhea and cataracts in the older individuals with the homozygous 18 base pair insertion. Enzymatic testing confirmed significantly reduced transketolase activity. Elevated urinary excretion of erythritol, arabitol, ribitol, and pent(ul)ose-5-phosphates was detected, as well as elevated amounts of erythritol, arabitol, and ribitol in the plasma of affected individuals. Transketolase deficiency reduces NADPH synthesis and nucleic acid synthesis and cell division and could explain the problems with growth. NADPH is also critical for maintaining cerebral glutathione, which might contribute to the neurodevelopmental delays. Transketolase deficiency is one of a growing list of inborn errors of metabolism in the non-oxidative part of the pentose phosphate pathway.

Iron overload detection using pituitary and hepatic MRI in thalassemic patients having short stature and hypogonadism

OBJECTIVE

to assess the growth and pubertal development among a group of patients with β-Thalassemia Major (β-TM) and to evaluate the role of the pituitary gland and liver MRI signal intensity (SI) reduction in assessing and predicting the clinical severity of growth and pubertal dysfunctions.

METHODS

Thirty-eight patients with β-TM were examined and divided into two groups: Group I patients were of normal height and puberty and Group II patients had short statures and hypogonadism. Laboratory investigations included serum ferritin, LH, FSH, prolactin, TSH, and basal and dynamic growth hormones. Pituitary and liver MRIs were performed to assess the pituitary to fat (P/F) and liver to muscle (L/M) signal intensities (SI), respectively. Fifteen healthy and sex- and age-matched subjects were included as controls.

RESULTS

Both patient groups had significantly elevated serum ferritin and significantly decreased prolactin and IGF1 compared to control subjects. Group II showed a significant reduction in LH, FSH, and IGF1 and a significant increase in ferritin in comparison with Group I and the control group, and it had a highly significant reduction in both P/F and L/M SI in comparison with Group I (p<0.001 and 0.008, respectively). The reduced P/F ratio was significantly correlated with FSH and LH, and a cutoff for a P/F ratio ≥0.94 was obtained to differentiate between Group I and II.

CONCLUSION

MRI in conjunction with the P/F signal intensity ratio is a useful and noninvasive tool for the early diagnosis of pituitary iron overload.

A rare cause of short stature: transsphenoidal encephalocele

Basal encephaloceles are rare, accounting for about 1.5% of all encephaloceles. Transsphenoidal encephaloceles represent less than 5% of basal encephaloceles. Respiratory and feeding difficulties due to mass effect in the oral or nasal cavity and episodes of recurrent meningitis are the main clinical features. Diagnosis is established in the first year of life, but without characteristic facies, the diagnosis can be delayed to adolescence or adulthood. We report the case of a 10-year-old boy who presented with short stature and eventually was diagnosed with a growth hormone deficiency because of mass effect of transsphenoidal encephalocele. Unusual presentation of an encephalocele as a short stature is described.

Hypomorphism in human NSMCE2 linked to primordial dwarfism and insulin resistance

Structural maintenance of chromosomes (SMC) complexes are essential for maintaining chromatin structure and regulating gene expression. Two the three known SMC complexes, cohesin and condensin, are important for sister chromatid cohesion and condensation, respectively; however, the function of the third complex, SMC5-6, which includes the E3 SUMO-ligase NSMCE2 (also widely known as MMS21) is less clear. Here, we characterized 2 patients with primordial dwarfism, extreme insulin resistance, and gonadal failure and identified compound heterozygous frameshift mutations in NSMCE2. Both mutations reduced NSMCE2 expression in patient cells. Primary cells from one patient showed increased micronucleus and nucleoplasmic bridge formation, delayed recovery of DNA synthesis, and reduced formation of foci containing Bloom syndrome helicase (BLM) after hydroxyurea-induced replication fork stalling. These nuclear abnormalities in patient dermal fibroblast were restored by expression of WT NSMCE2, but not a mutant form lacking SUMO-ligase activity. Furthermore, in zebrafish, knockdown of the NSMCE2 ortholog produced dwarfism, which was ameliorated by reexpression of WT, but not SUMO-ligase-deficient NSMCE. Collectively, these findings support a role for NSMCE2 in recovery from DNA damage and raise the possibility that loss of its function produces dwarfism through reduced tolerance of replicative stress.

Long-term endocrinologic complications of cystinosis

AIM

Cystinosis is a rare autosomal recessive disorder that is characterized by defective cystine transport from lysosomes to cytoplasm and cystine crystal accumulation damaging many organs and tissues especially kidneys but extrarenal systems such as endocrine system. We aim to investigate endocrinologic complications of cystinosis

METHODS

In our study, twenty one patients were reviewed retrospectively for endocrinologic complications.

RESULTS

Eighteen (85.7%) had short stature, out of nine patients who reached pubertal age, five (55.5%) had pubertal delay, five patients (23.8%) had overt hypothyroidism and five patients (23.8%) had subclinical hypothyroidism with only elevated thyroid stimulating hormone (TSH) levels, seven (33.3%) had glucose intolerance, two (9.5%) had diabetes mellitus. Relation of these complications to age, renal functions and the dosage of cysteamine were studied.

CONCLUSION

Endocrinologic complications of cystinosis can be seen in pediatric population and it is important to understand underlying mechanisms.

[Complex case with respiratory, endocrine and digestive manifestations--late complications after a colic replacement of the esophagus for lye ingestion]

Long term complications after colic replacement of the esophagus are well known and their managment is known as being difficult, due to multiple associated comorbidities; we present the case of a 26-year-old patient with multiple late complications after a coloesophagoplaty for lye ingestion during childhood. The patient finally died despite all the eforts of treatement during a prolonged hospitalisation. We will try to analyse the key moments on patient's evolution and discuss other possible options in this case.

[Clinical condition and therapy of bone diseases]

Skeletal dysplasia is the term which represents disorders including growth and differentiation of bone, cartilage and ligament. A lot of diseases are included, and new disorders have been added. However, the therapy of most bone diseases is less well-established. Achondroplasia, hypochondroplasia, and osteogenesis imperfecta are most frequent bone diseases. There is no curative treatment for these diseases, however, supportive therapies are available ; for example, growth-hormone therapy for achondroplasia and hypochondroplasia, and bisphosphonate therapy for osteogenesis imperfecta. In addition, enzyme replacement therapy for hypophosphatasia is now on clinical trial.

Severe short stature due to 3-M syndrome with a novel OBSL1 gene mutation

3-M syndrome is an underdiagnosed autosomal recessive disorder characterized by severe pre- and postnatal growth retardation with minimal dysmorphic features and distinguishing radiological findings. We report a patient who was first admitted at 7.5 years of age. He was born to consanguineous parents with a birth weight of 2250 g. Physical examination revealed a severe short stature (height, 95 cm; SD score -5.64) and minimal dysmorphic features. Biochemistry, endocrine work-up, and karyotype were normal. Reevaluation at 16.5 years of age revealed a height of 128.5 cm (SD score -5.27), prominent forehead, anteverted nasal openings, fleshy nasal tip, full lips, malar hypoplasia, hyperlordosis, prominent heels, testicular volumes 8-10 mL, and pubic hair consistent with Tanner stage II. Growth hormone trial for a year resulted in inadequate height gain (3 cm). The diagnosis of 3-M syndrome was made upon typical findings (thin long bones with diaphyseal narrowing and tall lumbar vertebrae) in a recent skeletal survey. Genetic analysis disclosed a homozygote frame shift mutation in exon 2: c.457_458delinsT resulting in p.Gly153fs.

A case of GH deficiency and beta-thalassemia

A 23-year-old male patient, who suffers from beta-thalassemia major, came to us for an endocrine-metabolic evaluation. Medical history showed a diagnosis of heart disease with heart failure since the age of 16, type 1 diabetes mellitus diagnosed at the age of 18, treated with an intensive insulin therapy with a poor glycometabolic control. Patient performed regular blood transfusions and iron chelation with deferasirox. An echocardiogram revealed an enlarged left ventricle. Patient had undergone a comprehensive study of buoyancy both basal and hormone-stimulated and it was therefore carried out a diagnosis of GH deficiency and hypogonadotropic hypogonadism. A recombinant GH replacement therapy was then prescribed. After six months of therapy, the patient reported a net improvement of asthenic symptoms. Physical examination showed a reduction in abdominal adiposity in waist and an increase of 5 cm in stature. Laboratory tests showed an amelioration of glycometabolic control, such as to justify a reduction in daily insulin dose. The stature observed was thought appropriate to begin the administration of testosterone. Moreover, the cardiological framework showed a reduction of left ventricular dilatation, good ventricular motility, global minimum persistent tricuspid but not mitral regurgitation and no alteration on ECG.

A new clinical presentation associated with pontine clefting, hyperpigmentation and short stature in addition to craniofacial, cardiac and developmental anomalies

We report on a 13-year-old girl who was the first child of nonconsanguineous parents, and who suffered from short stature accompanied with mental retardation, generalized hyperpigmentation of the skin and craniofacial findings. Her cardiological examination revealed atrial septal defect, mitral valve prolapsus and atrial septal aneurysm. Brain scans revealed dilatation of the third and lateral ventricles and a pontine cleft. Growth hormone (GH) deficiency was observed during the evaluation of GH/IGF-I axis. All the laboratory tests performed including metabolic screening, conventional karyotype and oligonucleotide array were normal. Mutation analysis of the C2ORF3 7 gene revealed no mutation. The clinical signs seen in this patient likely represent a new dysmorphological syndrome which has not been previously described.

Cushing disease as possible cause of persistent growth failure despite growth hormone therapy in a small for gestational age male

Growth hormone (GH) therapy in children with small for gestational age (SGA) has been shown to be of significant therapeutic benefit. We report the case of an 11-year-old Caucasian male who developed early adrenarche, hypertension and insulin resistance on GH therapy for SGA and profound short stature (ht -5 SD). This patient demonstrated a poor response to GH therapy and developed physical and biochemical findings of insulin resistance responsive to metformin therapy. He remained hypertensive, however, and continued to have elevated serum dehydroepiandrosterone sulfate levels. Urinary free cortisol excretion was subsequently found to be elevated. The diagnosis of Cushing's disease was confirmed with inferior petrosal sinus sampling and pituitary MRI. The patient underwent partial adenohypophysectomy with resulting normalization of plasma cortisol levels and associated symptoms. Our patient's diagnosis of Cushing's disease was complicated by his past history of poor growth since birth and history of SGA. The signs of Cushing's disease did not overtly appear until GH therapy was initiated to help treat severe short stature. It is possible that the metabolic effects of GH therapy unmasked the presence of underlying Cushing's disease.

[Bone dysplasia with short limb]

We described the condition of the disease, clinical appearance, X-rays appearance, orthopaedic problems about Achondroplasia, Pseudoachondroplasia, Metaphyseal Chondrodysplasia (Schmid type) , Mesomelic dysplasia (Dyschondrosteosis) as a representative bone dysplasia who present a short stature with short limbs. Clinical features are almost evident at birth in the patient with Achondroplasia. However, in other cases, there is no specific finding on clinically and radiologically at birth. Clinical and radiological findings develop slowly from period for childhood. It is considered that the diagnosis is not difficult since each of them have characteristic clinical features and X-rays views, only if examining them carefully. Correct and rapid diagnosis would be important for having a good relationship with patients.

Reduced ability of C-type natriuretic peptide (CNP) to activate natriuretic peptide receptor B (NPR-B) causes dwarfism in lbab -/- mice

C-type natriuretic peptide (CNP) stimulates endochondrial ossification by activating the transmembrane guanylyl cyclase, natriuretic peptide receptor-B (NPR-B). Recently, a spontaneous autosomal recessive mutation that causes severe dwarfism in mice was identified. The mutant, called long bone abnormality (lbab), contains a single point mutation that converts an arginine to a glycine in a conserved coding region of the CNP gene, but how this mutation affects CNP activity has not been reported. Here, we determined that 30-fold to greater than 100-fold more CNP(lbab) was required to activate NPR-B as compared to wild-type CNP in whole cell cGMP elevation and membrane guanylyl cyclase assays. The reduced ability of CNP(lbab) to activate NPR-B was explained, at least in part, by decreased binding since 10-fold more CNP(lbab) than wild-type CNP was required to compete with [125I][Tyr0]CNP for receptor binding. Molecular modeling suggested that the conserved arginine is critical for binding to an equally conserved acidic pocket in NPR-B. These results indicate that reduced binding to and activation of NPR-B causes dwarfism in lbab(-/-) mice.

[Growth hormone therapy for children with chronic diseases]

Growth disorders are commonly observed in children suffering from chronic diseases. The pathogenesis of growth failure is multifactorial. In chronic inflammatory diseases such as juvenile idiopathic arthritis and inflammatory bowel disease, growth is also affected by pro-inflammatory cytokines. Patients with chronic diseases might also become growth hormone (GH) deficient. However, normal or increased GH secretion with reduced plasma concentrations of insulin-like growth factor-I indicate a degree of GH insensitivity in some patients. Growth damage can increase with specific treatments, especially if glucocorticoids are used. GH therapy has been used to reduce the consequences of the disease and long-term steroid therapy in these patients. In this review, it is reported the encouraging results of GH treatment in growth-retarded children with chronic diseases, both in well defined indications as well in situations still under investigation.

Bilateral total hip arthroplasty in Morquio-Brailsford's syndrome: a report of two cases

We report two cases of bilateral cementless total hip arthroplasty in two young women affected by Morquio-Brailsford syndrome. Morquio-Brailsford disease belongs to the mucopolysaccharidoses; it shows growth retardation with disproportional dwarfism. Usually patients are affected by a severe joint degeneration from their 2nd or 3rd decade. Young age, severe dysplasia, and joint size are the main technical problems for a total hip replacement. Accurate radiographic and CT planning allows the use of standard prostheses instead of custom-made ones.

[Physical development of the teenagers who were exposed to radiation in utero after the accident on the Chernobyl Nuclear Power Plant]

Some features of physical development of teenagers exposed to radiation during utero development are revealed. These teenagers have been found to have more often, than in the control group disorders connected with harmonicity of physical development. Thus in the group of teenagers who have been exposed to acute radiation in utero period of their development prevails tall young men and girls while among the teenagers who have been born in 1986 and stayed living in the polluted territories low growth, subnanysm and nanysm is more often observed.

Floating-Harbor syndrome: case report

Floating-Harbor syndrome is a rare disorder which is clinically characterized by short stature, retarded speech development, delayed bone ages, triangular face, bulbous nose and thin lips. We described two cases with Floating-Harbor syndrome and briefly reviewed the relevant literature.

[Low height and rare diseases]

Low stature is the main reason of consultation in paediatric endocrinology. In a high percentage of cases, its etiology is clear and fundamentally answers to variants of normality. However, in approximately 20% of cases low stature is pathological and requires exhaustive studies. The association of rare diseases (RD) with low height is very frequent. In this article we review the etiology of low height, describing: - The genetic forms of the growth hormone (GH), whether isolated or associated with malformations of the average line or others. - Those which are of great importance due to their clinical repercussion, such as Turner's Syndrome, Noonan's Syndrome and Willi-Prader's Syndrome. - The frequent osseous dysplasias, in some cases with genetic alterations of the SHOX gene, situated in the short arm of the Xp chromosome. The importance of these diagnoses lies in the possibility of carrying out early and efficient treatment, in some of them, with GH. In conclusion, the diagnosis of rare diseases with low height is a current and normal challenge in paediatric endocrinology due to the great advances in molecular genetics and the possibility of treatment in some of them. It always involves a multidisciplinary approach due to the frequent association of pathology it presents, and, in its turn, it offers the possibility of carrying out timely genetic counselling.

IGF-I, IGFBP-3 and ALS generation test in Turner syndrome

OBJECTIVES

The pathophysiology of the short stature in girls with Turner syndrome (TS) is not well understood. The "IGF-I generation test" is used to assess the sensitivity to growth hormone. We compared the biochemical response to four days of growth hormone of TS and controls.

STUDY DESIGN

Pre-pubertal TS were recruited to participate in the study. Their siblings served as controls. IGF-I, IGFBP-3 and ALS were measured before and 5 days after using hGH (0.05mg/kg/day). Student-t test was used to compare the differences in their responses.

RESULTS

Eleven TS (mean age of 8.5+/-2.4) and 11 siblings (6 females and 5 males) (mean age of 7.0+/-2.0) participated in the study. The basal serum levels of IGF-I, IGFBP-3 and ALS were normal and not different between groups (p=0.62 for IGF-I, p=0.91 for IGFBP-3 and p=0.51 for ALS). The IGF-I generation test was positive in all controls and in 10/11 TS. The IGFBP-3 generation test was positive in 6/11 controls and 4/11 TS. After hGH the mean IGFBP-3 was lower in TS than in controls (p=0.08). The ALS response to hGH was not uniform between groups.

CONCLUSIONS

The IGF-I and ALS generation test results were not different between controls and TS. The IGFBP-3 results were higher in the control group but more than 50% of tested children did not pass. The IGF-I/IGFBP-3 generation tests, as presently done, did not help in the understanding of the short stature in TS. The use of different GH dosages and number of doses need to be investigated.

Hepatic disease as the first manifestation of progressive myoclonus epilepsy of Lafora

BACKGROUND

Lafora disease (LD; progressive myoclonus epilepsy type 2; EPM2) is an autosomal recessive disorder caused by mutations in the EPM2A and EPM2B genes. LD is characterized by the presence of strongly PAS-positive intracellular inclusions (Lafora bodies) in several tissues. Glycogen storage disease type IV (GSD-IV; Andersen disease) is an autosomal recessive disorder characterized by cirrhosis leading to severe liver failure. GSD-IV has been associated with mutations in the glycogen branching enzyme gene (GBE). Histopathologic changes of the liver in both diseases show an identical appearance, although cirrhosis has never been described in patients with LD. We report a LD family in which the proband presented severe liver failure at onset of the disease.

METHODS

Clinical histories, physical and neurologic examination, laboratory tests, EEGs, MRI of the brain, and liver or axillary skin biopsies were performed in the two affected siblings. The diagnosis was confirmed by molecular genetic analysis of the EPM2A, EPM2B, and GBE genes and loci.

RESULTS

During the first decade of life, abnormalities in liver function tests were detected in the two affected siblings. The proband's liver dysfunction was severe enough to require liver transplantation. Subsequently, both sibs developed LD. Mutation analysis of EPM2A revealed a homozygous Arg241stop mutation in both patients.

CONCLUSIONS

This is the first description of severe hepatic dysfunction as the initial clinical manifestation of LD. The phenotypic differences between the two affected siblings suggest that modifier genes must condition clinical expression of the disease outside the CNS.

[Severe chronic anemia and endocrine disorders in children]

Hemolytic anemias can induce various anomalies of the endocrine glands which can already be observed in children. Endocrine dysfunction is also found in the course of therapy for aplastic anemias, usually as undesirable side effects. In Europe, 2-9% of the population belongs to ethnic minorities at risk for developing hemolytic anemia. Pituitary affinity to iron deposition explains the high incidence of hypogonadism, puberty delay and growth retardation although other factors have to be considered. Growth hormone deficiency has to be ruled out as it can occur in a minority of subjects with thalassemia and sickle-cell disease (drepanocytosis). Diabetes mellitus, hypothyroidism and hypoparathyroidism may also develop. Follow-up includes close monitoring of growth and pubertal development in order to guide therapeutic interventions.

Oxidoreductase interactions include a role for ERp72 engagement with mutant thyroglobulin from the rdw/rdw rat dwarf

Newly synthesized thyroglobulin (Tg), the secretory glycoprotein that serves as precursor in thyroid hormone synthesis, normally forms transient covalent protein complexes with oxidoreductases of the endoplasmic reticulum (ER). The Tg-G2320R mutation is responsible for congenital hypothyroidism in rdw/rdw rats, in which a lack of secondary thyroid enlargement (goiter) implicates death of thyrocytes as part of disease pathogenesis. We found that mutant Tg-G2320R was retained within the ER with no detectable synthesis of thyroxine, had persistent exposure of free cysteine thiols, and was associated with activated ER stress response but incomplete ER-associated degradation (ERAD). Tg-G2320R associated with multiple ER resident proteins, most notably ERp72, including covalent Tg-ERp72 interactions. In PC Cl3 thyrocytes, inducible overexpression of ERp72 increased the ability of cells to maintain Tg cysteines in a reduced state. Noncovalent interactions of several ER chaperones with newly synthesized Tg-G2320R diminished over time in parallel with ERAD of the mutant protein, yet a small ERAD-resistant Tg fraction remained engaged in covalent association with ERp72 even 2 days post-synthesis. Such covalent protein aggregates may set the stage for apoptotic thyrocyte cell death, preventing thyroid goiter formation in rdw/rdw rats.

[Neurocognitive and psychosocial development in SGA and the indication for growth hormone therapy]

After recent approval of treatment indication for growth hormone therapy (GHT) in SGA (small for gestational age) treatment expectations do not only refer to improvement of growth parameters but also to enhancement of suspected impairments of neurocognitive, behavioural and educational development. Clinical prognosis, however, is difficult which specific developmental risks are to be expected in the individual case and if their course may response to GHT. The paper reviews recent findings of clinical and population-based studies on neurocognitive and psychosocial outcome in SGA and delineates an integrative framework on the emergence and course of potential developmental risk comprising three major causes: Conclusions are drawn for the clinical differentiation of specific adaptation difficulties towards short stature versus global, short stature independent behavioral disorders. Psychosocial outcome parameters can be expected to respond best to endocrinological growth stimulation in conditions with a high specific short stature related maladjustment; in turn, the relevance of child psychology interventions increases in conditions with global disturbance and short stature independent origin.

Inactivating mutations of G protein-coupled receptors and diseases: Structure-function insights and therapeutic implications

Since the discovery of the first rhodopsin mutation that causes retinitis pigmentosa in 1990, significant progresses have been made in elucidating the pathophysiology of diseases caused by inactivating mutations of G protein-coupled receptors (GPCRs). This review aims to compile the compelling evidence accumulated during the past 15 years demonstrating the etiologies of more than a dozen diseases caused by inactivating GPCR mutations. A generalized classification scheme, based on the life cycle of GPCRs, is proposed. Insights gained through detailed studies of these naturally occurring mutations into the structure-function relationship of these receptors are reviewed. Therapeutic approaches directed against the different classes of mutants are being developed. Since intracellular retention emerges as the most common defect, recent progresses aimed at correcting this defect through membrane permeable pharmacological chaperones are highlighted.

Thoracolumbar syrinx in association with Williams syndrome

Williams syndrome is a genetic condition caused by a deletion on chromosome 7. Clinically it consists of multiple cardiovascular and craniofacial structural abnormalities as well as developmental delay, specific cognitive difficulties, and a characteristic personality. Although scoliosis is a noted manifestation of the disorder, syrinx in association with Williams syndrome has not been reported previously in the literature. Here we present the case of a child with Williams syndrome, scoliosis, and a thoracolumbar syrinx that was successfully treated surgically. We recommend that children with Williams syndrome and scoliosis undergo preoperative evaluation of the spinal cord, as well as the spinal column, so that correctable lesions such as a syrinx are not overlooked. Although syrinxes are often associated with scoliosis, the association in this case of syrinx and Williams syndrome could imply the existence of a genetic contribution to syrinx formation on chromosome 7.

Long-term height gain of prematurely born children with neonatal growth restraint: parallellism with the growth pattern of short children born small for gestational age

BACKGROUND

It is unknown whether children born very preterm (< 32 weeks' gestation) with appropriate size for gestational age, who grow poorly in the first postnatal months (ie, preterm growth restraint), show a similar growth pattern as children born small for gestational age.

OBJECTIVE

Childhood growth and adult height of children with preterm growth restraint were compared to those of very preterm small-for-gestational-age and non-preterm-growth-restraint children.

METHODS

Data were drawn from the Project on Preterm and Small-for-Gestational-Age Infants cohort. Preterm growth restraint was considered to have occurred after appropriate-size-for-gestational-age birth and if length and/or weight was below -2 SD score at 3 months postterm.

RESULTS

Among 380 very preterm children, 274 experienced no preterm growth restraint and showed near-normal growth, whereas 79 (21%) experienced preterm growth restraint and subsequently displayed a growth pattern similar to that of very preterm small-for-gestational-age children (n = 27). Adult height of these children was -1.1 to -1.2 SD score. Very preterm small-for-gestational-age and preterm-growth-restraint children with a height below -2 SD score at 5 years had an adult height of approximately -2.5 SD score.

CONCLUSIONS

Childhood growth and adult height were similar in very preterm small-for-gestational-age and preterm-growth-restraint children. These long-term findings further strengthen the plausibility of extending the small-for-gestational-age indication for growth hormone therapy in such a way that preterm-growth-restraint children are no longer excluded if they have a short stature persisting beyond the age of approximately 5 years.

The impact of genotype on endocrine complications in thalassaemia major

BACKGROUND

The clinical severity in thalassaemia major (TM) depends on the underlying mutations of the beta-globin gene and the degree of iron overload.

OBJECTIVE

The aim of the study was to investigate the impact of genotype on the development of endocrine complications in TM in our center.

SUBJECTS AND METHODS

126 (62 males, 64 females) thalassaemic patients of Greek Cypriot origin with a mean age of 31.2 (17-68) yr were included in the study. All patients, who were on the standard treatment protocol, were subsequently divided into two groups according to their genotype, group A (92): TM with no mitigating factor and group B (34): TM carrying one or more mitigating factors in the beta- and/or alpha-globin genes. Iron overload calculation was based on the amount of red cell consumption and the mean ferritin level over a 12-year period. Statistical analysis was performed with the SPSS program.

RESULTS

Patients in group A, who were consuming larger amounts of blood on transfusions, were more likely to develop hypogonadism (P = 0.001) compared with patients in group B, despite their similar mean ferritin levels. The incidence of other endocrinopathies (short stature, hypothyroidism, and diabetes mellitus) was similar in the two groups. The prevalence of hypothyroidism in splenectomized patients was significantly higher (P = 0.005), whereas the presence of hypogonadism, impaired glucose homeostasis and insulin resistance, although more frequent, was not statistically significant. The clinical severity of TM had no impact on bone mineral density (BMD) in both men and women. BMD was only influenced by gonadal function.

CONCLUSIONS

This study demonstrates that the underlying genetic defect in TM is a contributing factor for gonadal dysfunction, because the patients with the more severe defects have a greater rate of iron loading through higher red cell consumption.

Macroprolactinemia in childhood and adolescence: a cause of hyperprolactinemia

Human prolactin consists of multiple forms of different sizes including three major prolactin (PRL) species, termed as little, big, and big-big PRL. If serum contains big-big PRL, it is termed macroprolactinemia; no symptoms of hyperprolactinemia develop due to low biological activity of big-big PRL. There are still few data regarding macroprolactinemia in children and adolescents. In this paper we describe six patients with macroprolactinemia, one of whom was asymptomatic and the other five either had headache, menstrual disturbance, short stature, increased hair growth or early puberty, compatible with high PRL levels. Two of the cases had microadenoma. Initial mean +/- SD PRL levels of the patients were 75.2 +/- 22.8 ng/ml (range: 42.3-105.2 ng/ml). Macroprolactin analysis revealed big-big PRL levels of the patients ranging between 21.6-98.6 ng/ml. It was noteworthy that bromocriptine (BRC) therapy started in three patients caused an abrupt decrease in PRL levels. It may be concluded that macroprolactinemia should be taken into account in the differential diagnosis of hyperprolactinemia in childhood and adolescence, whether or not they have relevant clinical symptoms.

periostin null mice exhibit dwarfism, incisor enamel defects, and an early-onset periodontal disease-like phenotype

Periostin was originally identified as an osteoblast-specific factor and is highly expressed in the embryonic periosteum, cardiac valves, placenta, and periodontal ligament as well as in many adult cancerous tissues. To investigate its role during development, we generated mice that lack the periostin gene and replaced the translation start site and first exon with a lacZ reporter gene. Surprisingly, although periostin is widely expressed in many developing organs, periostin-deficient (peri(lacZ)) embryos are grossly normal. Postnatally, however, approximately 14% of the nulls die before weaning and all of the remaining peri(lacZ) nulls are severely growth retarded. Skeletal analysis revealed that trabecular bone in adult homozygous skeletons was sparse, but overall bone growth was unaffected. Furthermore, by 3 months, the nulls develop an early-onset periodontal disease-like phenotype. Unexpectedly, these mice also show a severe incisor enamel defect, although there is no apparent change in ameloblast differentiation. Significantly, placing the peri(lacZ) nulls on a soft diet that alleviated mechanical strain on the periodontal ligament resulted in a partial rescue of both the enamel and periodontal disease-like phenotypes. Combined, these data suggest that a healthy periodontal ligament is required for normal amelogenesis and that periostin is critically required for maintenance of the integrity of the periodontal ligament in response to mechanical stresses.