A Recurrent Mutation in Growth Hormone Receptor (GHR) Gene Underlying Laron-type Dwarfism in a Pakistani Family.

Laron syndrome (LS) is a rare autosomal recessively segregating disorder of severe short stature. The condition is characterized by short limbs, delayed puberty, hypoglycemia in infancy, and obesity. Mutations in growth hormone receptor (GHR) have been implicated in LS; hence, it is also known as growth hormone insensitivity syndrome (MIM-262500). Here we represent a consanguineous Pakistani family in which three siblings were afflicted with LS. Patients had rather similar phenotypic presentations marked with short stature, delayed bone age, limited extension of elbows, truncal obesity, delayed puberty, childish appearance, and frontal bossing. They also had additional features such as hypo-muscularity, early fatigue, large ears, widely-spaced breasts, and attention deficit behavior, which are rarely reported in LS. The unusual combination of the features hindered a straightforward diagnosis and prompted us to first detect the regions of shared homozygosity and subsequently the disease-causing variant by next generation technologies, like SNP genotyping and exome sequencing. A homozygous pathogenic variant c.508G>C (p.(Asp170His)) in GHR was detected. The variant is known to be implicated in LS, supporting the molecular diagnosis of LS. Also, we present detailed clinical, hematological, and hormonal profiling of the siblings.

Growth hormone insensitivity: diagnostic and therapeutic approaches.

INTRODUCTION: Growth hormone resistance defines several genetic (primary) and acquired (secondary) pathologies that result in completely or partially interrupted activity of growth hormone. An archetypal disease of this group is the Laron-type dwarfism caused by mutations in growth hormone receptors. The diagnosis is based on high basal levels of growth hormone, low insulin like growth factor-I (IGF-1) level, unresponsiveness to IGF generation test and genetic testing. Recombinant IGF-1 preparations are used in the treatment CONCLUSION: In this article, clinical characteristics, diagnosis and therapeutic approaches of the genetic and other diseases leading to growth hormone insensitivity are reviewed.

The E180splice mutation in the GHR gene causing Laron syndrome: witness of a Sephardic Jewish exodus from the Iberian Peninsula to the New World?

Laron syndrome (LS) is a genetic disorder caused by mutations in the growth hormone receptor (GHR) gene. The most frequent GHR mutation is E180splice (rs121909360), which was initially found in an inbred population of Spanish descent in Ecuador and subsequently in Israel, Brazil, Chile, and the United States. The aim of the present study is to determine if the E180splice mutation arose from a common origin. We studied 22 patients with LS from Ecuador, Israel (of Moroccan origin), Brazil, Chile, and the United States (of Mexican origin) who were homozygous for the E180splice mutation and compared them to control individuals for markers surrounding the GHR, intragenic polymorphisms, and Y-chromosome STR. An identical haplotype was found in all but one of the subjects carrying the E180splice mutation: D5S665: 150/150; D5S2082: 192/192; D5S2087: 246/246; rs6179 G/G; and rs6180 C/C. One patient differed from the others only at D5S2082 (168/192). This haplotype is rare (~1%) in control individuals and confirmed that the E180splice-associated haplotype was not derived from independent origins but represented recombination from a common ancestor. The analysis of paternal lineage markers showed that 50% belong to haplogroup R1b (found in Portugal and Spain) and 40% to haplogroups J and E (typical in the Middle East and in Eastern European Jews). The germline E180Splice mutation appears to have originated from a single common ancestor. The presence of Y-chromosome markers associated with Sephardic populations in persons harboring the E180splice mutation provides genetic evidence in support of the historical tracking of the exodus of this specific population.

Laron Syndrome: A Tale of Two Siblings.

Primary growth hormone (GH) resistance or growth hormone insensitivity syndrome, also called Laron syndrome, is a hereditary disease caused by mutations in the GH receptor or in the post-receptor signaling pathway. This disorder is characterized by postnatal growth failure resembling GH deficiency. Differentiating the two conditions is necessary. We present the cases of two siblings, a 16-year-old female and a 9-year-old male, born from a consanguineous union. Both had normal birth weights with subsequent severe short stature and delayed teeth eruption, with no features suggestive of any systemic illness. Serum insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein 3 (IGFBP3) were both low. Suspecting GH deficiency, provocative testing with clonidine was done revealing peak growth hormone >40 ng/mL in both patients. In view of low IGF1 and IGFBP3 and high GH on stimulation, IGF1 generation test was done for both siblings, with values supporting the diagnosis of GH insensitivity or Laron syndrome.

Challenges in the care of individuals with severe primary insulin-like growth factor-I deficiency (SPIGFD): an international, multi-stakeholder perspective.

BACKGROUND: Severe primary insulin-like growth factor-I (IGF-I) deficiency (SPIGFD) is a rare growth disorder characterized by short stature (standard deviation score [SDS] ≤ 3.0), low circulating concentrations of IGF-I (SDS ≤ 3.0), and normal or elevated concentrations of growth hormone (GH). Laron syndrome is the best characterized form of SPIGFD, caused by a defect in the GH receptor (GHR) gene. However, awareness of SPIGFD remains low, and individuals living with SPIGFD continue to face challenges associated with diagnosis, treatment and care. OBJECTIVE: To gather perspectives on the key challenges for individuals and families living with SPIGFD through a multi-stakeholder approach. By highlighting critical gaps in the awareness, diagnosis, and management of SPIGFD, this report aims to provide recommendations to improve care for people affected by SPIGFD globally. METHODS: An international group of clinical experts, researchers, and patient and caregiver representatives from the SPIGFD community participated in a virtual, half-day meeting to discuss key unmet needs and opportunities to improve the care of people living with SPIGFD. RESULTS: As a rare disorder, limited awareness and understanding of SPIGFD amongst healthcare professionals (HCPs) poses significant challenges in the diagnosis and treatment of those affected. Patients often face difficulties associated with receiving a formal diagnosis, delayed treatment initiation and limited access to appropriate therapy. This has a considerable impact on the physical health and quality of life for patients, highlighting a need for more education and clearer guidance for HCPs. Support from patient advocacy groups is valuable in helping patients and their families to find appropriate care. However, there remains a need to better understand the burden that SPIGFD has on individuals beyond height, including the impact on physical, emotional, and social wellbeing. CONCLUSIONS: To address the challenges faced by individuals and families affected by SPIGFD, greater awareness of SPIGFD is needed within the healthcare community, and a consensus on best practice in the care of individuals affected by this condition. Continued efforts are also needed at a global level to challenge existing perceptions around SPIGFD, and identify solutions that promote equitable access to appropriate care. Medical writing support was industry-sponsored.

Cochlear hearing loss in patients with Laron syndrome.

The aim of this prospective clinical study was to test auditory function in patients with Laron syndrome, either untreated or treated with insulin-like growth factor I (IGF-I). The study group consisted of 11 patients with Laron syndrome: 5 untreated adults, 5 children and young adults treated with replacement IGF-I starting at bone age <2 years, and 1 adolescent who started replacement therapy at bone age 4.6 years. The auditory evaluation included pure tone and speech audiometry, tympanometry and acoustic reflexes, otoacoustic emissions, loudness dynamics, auditory brain stem responses and a hyperacusis questionnaire. All untreated patients and the patient who started treatment late had various degrees of sensorineural hearing loss and auditory hypersensitivity; acoustic middle ear reflexes were absent in most of them. All treated children had normal hearing and no auditory hypersensitivity; most had recordable middle ear acoustic reflexes. In conclusion, auditory defects seem to be associated with Laron syndrome and may be prevented by starting treatment with IGF-I at an early developmental age.

Diagnosis and management of disorders of IGF-I synthesis and action.

After a proper medical history, growth analysis and physical examination of a short child, followed by radiological and laboratory screening, the clinician may decide to perform genetic testing. We recently proposed several clinical algorithms that can be used to establish the diagnosis. GH insensitivity (primary IGF-I deficiency) can be caused by genetic defects in GHR, STAT5B, IGF1, IGFALS, which all have their specific clinical and biochemical characteristics. IGF-I resistance is seen in heterozygous defects of IGF1R. If besides short stature additional abnormalities are present, these should be matched with known dysmorphic syndromes. If no obvious candidate gene can be determined, a whole genome approach can be taken to check for deletions, duplications and/or uniparental disomies (SNP-array) or whole exome sequencing. Children with GHR defects, and presumably STAT5B and homozygous IGF1 defects, can be treated with rhlGF-I. Children with IGF1R defects and mild or heterozygous IGF1 defects respond to GH treatment.

GH deficiency in adult B-thalassemia major patients and its relationship with IGF-1 production.

Endocrine complications in Β-thalassemia represent a prominent cause of morbidity. Above all, dysfunction of GH-IGF-1 axis is of a major concern because of its pathogenic role on cardiac and bone disease, frequently described in this clinical setting. The aim of this paper is to analyze GH-IGF-1 axis in a cohort of 25 adult patients affected by Β-thalassemia. We found that GH deficiency was present in only 8% of our patients if diagnosis was based on GH peak below 9µg/L to two GH provocative tests instead of only one, and was mainly related to iron overload. On the contrary, IGF-1 production was impaired in a higher percentage of patients (72%), without significant correlation with iron burden. Of note, patients with hepatitis C virus infection showed lower IGF-1 concentrations than uninfected subjects despite a normal GH reserve, suggesting that partial GH insensitivity at the post-receptor level may play a key role in IGF-1 deficiency described in thalassemic patients.

Growth hormone and adrenal response to intramuscular glucagon test and its relationship to IGF-1 production and left ventricular ejection fraction in adult B-thalassemia major patients.

In patients with b-thalassemia major (TM), the anterior pituitary gland is particularly sensitive to free radical stresses. It has been reported that the GH deficiency (GHD) may be secondary to either pituitary or hypothalamic dysfunction. The duration of the disease, the patient's age and the severity of iron overload are the most important factors responsible for the defect of growth hormone (GH) secretion. Recent reports have documented a frequency of severe growth hormone deficiency in 13%-32% of patients with b-thalassemia major. All of these patients underwent GH-releasing hormone (GH-RH) plus arginine (ARG) testing. We undertook the present study to evaluate the GH and adrenal response during glucagon stimulation test (GST) in patients with TM because the GH-RH plus ARG test in patients with hypothalamic GHD may be misleading. Thirty-three adult TM patients were recruited (mean age 36.6 years). Fifty four percent were included in the severe GHD group (GH peak below 3mg/l). The IGF-1 level in TM patients was consistently low (60.3 ± 35.3 mg/l) and 86.6% of patients with a normal GH response to GST had a low IGF-1 level. These findings are also indicative of a relative resistance to GH. In eight out of 18 TM patients (44.4%), the GHD was associated with hypogonadotropic hypogonadism. A positive correlation was found between GH peak after GST and IGF-1 level (r = 0.8, p: 0.003) and a negative correlation between the age of female TM patients and GH peak (r = 0.711, p: 0.007). All patients but one had no evidence of cardiac iron overload (mean T2* 30.4 ± 8.2 ms; range 14-44 ms). The mean LVEF (%) in TM patients was no different when compared to healthy controls. However, three patients with severe GHD and normal T2*were found to have reduced LVEF.One patient (4%) had a peak cortisol response to GST compatible to adrenal insufficiency. Nausea, headache and\or hypoglycemia occurred in 3 patients (12%) during GST. In conclusion, our study demonstrates that the presence of GHD is frequent in adult TM patients. According to the international guidelines for medical practice, we believe that before considering hormone replacement therapy, a second test to confirm the diagnosis of GHD and adrenal insufficiency is required.

Identification and In Vitro Functional Verification of Two Novel Mutations of GHR Gene in the Chinese Children with Laron Syndrome.

Purpose: Laron syndrome (LS) is a severe growth disorder caused by GHR gene mutation or post-receptor pathways defect. The clinical features of these patients collected in our present study were summarized, GHR gene variants were investigated and further in vitro functional verification was carried out. Methods: Four patients with LS were collected, their clinical characteristics were summarized, genomic DNA was extracted, and GHR gene was amplified and sequenced. GHR wild type (GHR-WT) and mutant GHR expression plasmids were constructed, and transiently transfected into HepG2 cells and HEK293T cells to observe the subcellular distribution of the GHR protein by immunofluorescence and to determine the expression of GHR and its post-receptor signaling pathway changes by Western blotting. Results: All of the four patients were male, and the median height was -4.72 SDS. Four GHR gene variants including c.587A>C (p.Y196S), c.766C>T (p.Q256*), c.808A>G (p.I270V) and c.1707-1710del (p.E570Afs*30) were identified, and the latter two were novel mutations. The results of mutant GHR plasmids transfection experiments and immunofluorescence assay showed that the subcellular distribution of GHR-Q256* and GHR-E570Afs*30 mutant proteins in HepG2 and HEK293T cells presented with a unique ring-like pattern, gathering around the nucleus, while GHR-Y196S mutant protein was evenly distributed on HepG2 cell membrane similar to GHR-WT. The GHR protein levels of HepG2 cells transiently transfected with GHR-Y196S, GHR-Q256* and GHR-E570Afs*30 were all significantly lower when compared with cells transfected with GHR-WT (P<0.05). Further mutant GHR post-receptor signal transduction investigation demonstrated that GH induced phosphorylated STAT5 levels of HepG2 cells transfected with three mutant plasmids were all significantly decreased in comparison with that of GHR-WT (P<0.05). Conclusions: Two novel GHR gene mutations (I270V and E570Afs*30) were found in our patients with LS. GHR mutations influenced the subcellular distribution and GHR protein levels, then led to the impaired post-receptor signal transduction, suggesting that the GHR mutations contributed to the pathological condition of LS patients.

Diagnosis and management of primary insulin-like growth factor-I deficiency: current perspectives and clinical update.

With the availability of recombinant human (rh) IGF-I as a new therapeutic agent, the criteria for diagnosis and strategies for management of growth deficiencies continue to evolve. This supplement provides a clinical update on molecular, therapeutic, and metabolic aspects of the management of short stature associated with insulin-like growth factor-I deficiency (IGFD). Several distinct, single-gene defects associated with primary IGFD now have been identified. The first section of this supplement focuses on selecting certain patients for specific genetic testing of the GH/IGF-I axis, based on previously obtained clinical and biochemical assessments. Management of short stature in children responding poorly to rhGH and definitions of a good and poor response are discussed in the next section. In addition, the authors further address different methods to help practicing clinicians predict and assess GH response, review the effect of rhGH on final adult height, and discuss the role IGF-I may have in the therapeutic approach to short stature. Finally, the metabolic aspects related to the treatment of short stature are discussed in the third part of this supplement.

Hand size and growth in untreated and IGF-I treated patients with Laron syndrome.

UNLABELLED: We have previously reported on the linear growth, growth of the head circumference and foot length in untreated and IGF-I treated patients with Laron syndrome (LS) (primary GH insensitivity). AIM: To assess the size and growth of the hands in patients with LS from early childhood to adult age. PATIENTS: Ten IGF-I treated children with LS (4 M, 6 F) and 24 untreated patients (10 M, 14 F) were studied. METHODS: Measurements of palm length were made on available standardized hand X-rays from infancy to adult age. The measurements were compared to normal references and SD values were calculated for each measurement. The growth of the hand was compared to the concomitant height of the body. RESULTS: Hand SDS in untreated patients with LS decreased with age, from a mean of -2.8 +/- 0.7 (age 1-3 years) to -7.3 +/- 0.8 (age 13-15 years) and to -9.0 +/- 3.9 (age 40-50 years). During 9 years of IGF-I treatment the hand size deficit SDS did not improve in contradistinction to the height SDS which decreased from -6.2 +/- 1.2 to -3.9 +/- 0.5. CONCLUSION: Congenital IGF-I deficiency, as in Laron syndrome, profoundly affects the size and growth of the hand as part of its growth retardation characteristics, resulting in acromicria.

[Congenital adrenal hyperplasia and growth hormone deficiency. Special care in transition to adulthood]. / Adrenogenitales Syndrom und Wachstumshormonmangel. Betreuung beim Ubergang zum Erwachsenenalter.

Children with chronically endocrine diseases should be treated as young adults by adult endocrinologists. To optimize the transfer from the pediatric to adult endocrinologist, the model of a common transition clinic has been developed. Within this setting it should be possible to exchange experiences, extend the knowledge and understanding of the disease with the other side, and to provide for the patient an optimal outpatient care. This model, however, has only been sporadically realized to date. To set an example for the problems of the transition into adult endocrinology, we used two different endocrine diseases, the classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency, and the childhood-onset growth hormone deficiency. Specific problems for this transfer to adult care are the fixation of the patients to their pediatricians and the lack of comprehension in the need of a long term and continuous therapy. The consequence is a dramatic impairment in the quality of the therapy.

Laron syndrome related to homozygous growth hormone receptor c.784>C mutation in a patient with hypoplastic pulmonary arteries.

Laron syndrome, also known as growth hormone insensitivity, is an autosomal recessive disorder characterised by short stature due to mutations or deletions in the growth hormone receptor (GHR), leading to congenital insulin-like growth factor 1 (IGF1) deficiency. Cardiac abnormalities, such as patent ductus arteriosus or peripheral vascular disease are rare in patients with Laron syndrome, but cardiac hypertrophy has been observed after IGF1 therapy. In this report, we present a 10-year-and-5-month-old girl with severe peripheral-type pulmonary artery hypoplasia and Laron syndrome related to homozygous GHR c.784>C mutation.

A 42-Year-Old Woman with Untreated Growth Hormone Insensitivity, Diabetic Retinopathy, and Gene Sequencing Identifies a Variant of Laron Syndrome.

BACKGROUND Growth hormone insensitivity and reduced levels of insulin-like growth factor-1 (IGF-1) are associated with metabolic syndrome that includes obesity, hyperglycemia, type 2 diabetes mellitus, and dyslipidemia. Laron syndrome is a rare autosomal recessive condition associated with insensitivity to growth hormone that results in short stature and metabolic syndrome and is usually diagnosed in childhood. This report is of a 42-year-old Mexican woman with untreated growth hormone insensitivity and diabetic retinopathy, in whom gene sequencing supported the identification of a variant of Laron syndrome. CASE REPORT A 42-year-old Mexican woman with untreated growth hormone insensitivity, metabolic syndrome, and type 2 diabetes mellitus was diagnosed with cataracts, severe retinopathy and hearing loss. She was investigated for genetic causes of reduction in IGF-1. Next-generation sequencing (NGS) showed genetic changes in the growth hormone and IGF-1 axis. The patient's phenotype and genetic changes were consistent with Laron syndrome. CONCLUSIONS The early detection of reduced IGF-1 and identification of the cause of growth hormone insensitivity require international consensus on the approach to diagnosis and treatment methods, including effective IGF-1 replacement therapy. Early diagnosis may reduce the clinical consequences of complications that include short stature the development of metabolic syndrome, type 2 diabetes mellitus, and retinopathy.

Cardiac examination in children with Laron syndrome undergoing mecasermin therapy.

BACKGROUND: Laron syndrome (LS), which can be defined as primary growth hormone resistance or insensitivity, is a rare genetic disease inherited by an autosomal recessive trait. Although it is undistinguishable from growth hormone deficiency, LS has high levels of growth hormone, but insulin-like growth factor (IGF-1) cannot be synthesized. Mecasermin treatment is the only option for the patients who suffer from LS. This study aims to research cardiac findings of children with LS, who receive treatment with mecasermin. METHODS: The study enrolled five children four males and one female, 4 M/1 F with LS, two of whom were siblings with a mean age of 6.3±2.1 years, a body weight of 13.36±4.74 kg, a height of 88±8.7 cm, and a body mass index (BMI) of 16.47±3.35. Their demographic data were obtained from their family and files. The children received mecasermin via subcutaneous injection at 0.04-0.12 µg/kg doses twice per day. The duration of mecasermin treatment was 8-53 months. All of them were examined clinically by electrocardiogram and echocardiogram. RESULTS: Their cardiac examinations were normal, except for one case, who had systolic murmur at cardiac auscultation. Arrhythmia was not observed on their electrocardiograms. The echocardiograms did not show a significant congenital cardiac anomaly. Their cardiac measure and functions were within normal ranges. The echocardiogram of the child with the murmur showed mitral and tricuspid insufficiency. The Doppler images showed pulmonary hypertension findings. These findings were proven by angiography. The vasoreactivity test results of that patient were negative. No reason could be found for the observed pulmonary hypertension. We diagnosed this finding as a primary pulmonary hypertension and Bosentan therapy was started. CONCLUSIONS: In this study, we showed that cardiac findings were consistent with previous studies. To the best of our knowledge, the observed pulmonary hypertension in children with LS, who received treatment with or without mecasermin, is reported for first time in the literature.

Compound heterozygosity for two GHR missense mutations in a patient affected by Laron Syndrome: a case report.

BACKGROUND: Mutations localized in the Growth Hormone Receptor (GHR) gene are often associated with the pathogenesis of Laron Syndrome, an autosomal recessive hereditary disorder characterized by severe growth retardation. Biochemically, patients present normal to high circulating GH levels, in presence of very low or undetectable IGF-I levels, which do not rise after rhGH treatment. CASE PRESENTATION: We describe the case of a 3.8 years old girl with symmetrical short stature (-3.76 SDS), low IGF-1 and IGFBP-3, in presence of normal GH levels. Parents were not relatives and there was no family history of short stature. During the second day of birth, she developed severe hypoglycaemia that required glucose infusion. She presented frontal bossing and depressed nasal bridge. IGF-1 generation test showed no response, suggesting a GH resistance evidence. In the hypothesis of Laron Syndrome, we decided to perform a molecular analysis of Growth Hormone Receptor (GHR) gene. This analysis demonstrated that the patient was compound heterozygote for two missense mutations. CONCLUSIONS: GHR gene mutations are a well demonstrated cause of GH insensitivity. In heterozygous patients, probably the normal stature may be achieved by a compensatory mechanism of GH secretion or signalling. On the contrary, in homozygous or compound heterozygous patients these compensatory mechanisms are inadequate, and short stature may be the consequence.

[Laron syndrome: Presentation, treatment and prognosis]. / Syndrome de Laron : aspects diagnostiques, thérapeutiques et pronostiques.

Laron syndrome is a rare cause of short stature due to an abnormality of growth hormone receptor (GHR). It is characterized by poor phenotype-genotype correlation and geographic predilection essentially in the Mediterranean rim, the Middle East and Indian subcontinent. This syndrome corresponds to an endogenous and exogenous complete insensitivity of GH and manifests by early hypoglycemia, an extremely severe short stature and dysmorphic features contrasting with high levels of circulating GH. To date, treatment with recombinant IGF1 is the only treatment option that has improved the terrible prognosis in these patients but does not actually realize the conditions for genuine replacement therapy.