Variable phenotypic expression in a large Noonan syndrome family segregating a novel SOS1 mutation.

Noonan syndrome (NS) is an autosomal dominant multisystem condition with a variable phenotype. The most characteristic features are short stature, congenital heart defects, and recognizable facial features. Mutations in SOS1 are found in 10-20% of patients with NS. Different genotype-phenotype studies mention correlations between SOS1 mutations and some features, such as ectodermal abnormalities and specific facial features. We present a large NS family with a novel pathogenic mutation; SOS1 c.3134C>G, p.Pro1045Arg. Ten family members with NS are included with genetically confirmed mutation and clinical evaluation. The phenotype shows a broad spectrum from only few suggestive features for NS in the older generation to typical features in the youngest generation. We report on a novel pathogenic mutation in the SOS1 gene and a large clinical spectrum in a NS family with ten genetically confirmed affected individuals.

Perceived motor problems in daily life: Focus group interviews with people with Noonan syndrome and their relatives.

Studies from a patient perspective on motor performance problems in Noonan syndrome in daily life are lacking. The aims of this study were to provide insight into the motor performance problems that people with Noonan syndrome and/or their relatives experienced, the major consequences they suffered, the benefits of interventions they experienced, and the experiences with healthcare professionals they mentioned. We interviewed 10 adults with Noonan syndrome (two were joined by their parent), and 23 mothers (five of whom had Noonan syndrome), nine fathers (one of whom had Noonan syndrome) and one cousin who reported on 28 children with Noonan syndrome. People with Noonan syndrome reported particular problems related to pain, decreased muscle strength, fatigue, and clumsiness, which had an evident impact on functioning in daily life. Most participants believed that problems with motor performance improved with exercise, appropriate physiotherapy guidance, and other supportive interventions. Nevertheless, people with Noonan syndrome and/or their relatives did not feel heard and supported and experienced no understanding of their problems by healthcare professionals. This was the first study from a patient perspective that described the motor performance problems in people with Noonan syndrome, the major consequences in daily life, the positive experiences of interventions and the miscommunication with healthcare professionals. To achieve optimal support, healthcare professionals, as well as people with Noonan syndrome and/or their relatives themselves, should be aware of these frequently presented problems with motor performance. Research on these different aspects is needed to better understand and support people with Noonan syndrome.© 2016 Wiley Periodicals, Inc.

Noonan syndrome, the SOS1 gene and embryonal rhabdomyosarcoma.

Noonan Syndrome (NS) is an autosomal dominant condition characterized by short stature, facial dysmorphisms, and congenital heart defects, and is caused by mutations in either PTPN11, KRAS, NRAS, SHOC2, RAF1, or SOS1. Furthermore, NS is known for its predisposition to develop cancer, particularly hematological malignancies and specific solid tumors, mainly neuroblastoma and embryonal rhabdomyosacroma (ERMS). Until recently, however, cancer predisposition in NS patients with SOS1 mutations was not reported. Here we present a NS patient with a de novo germline SOS1 mutation (p.Lys728Ile) and ERMS. This heterozygous germline mutation was homozygously present in the ERMS of this patient due to an acquired uniparental disomy (UPD) of chromosome 2. In addition, several other chromosomal aberrations were encountered, some of which are known to recurrently occur in ERMS. Sequence analysis of the SOS1 gene in 20 sporadic ERMS tumors failed to reveal any pathogenic mutations, implicating that SOS1 is not a major player in the development of this tumor outside the context of NS.

Corrigendum to "Benign course after acute high dose levothyroxine intoxication in a 3-year-old boy".

[This corrects the article DOI: 10.1297/cpe.26.171.].

Denys-Drash syndrome and congenital diaphragmatic hernia: another case with the 1097G > A(Arg366His) mutation.

Congenital diaphragmatic hernia (CDH) is a disorder of the development of the lung and diaphragm and is associated with pulmonary hypoplasia and pulmonary hypertension. Denys-Drash syndrome (DDS) is a well-known syndrome caused by several different germline mutations in the WT1-gene. CDH in DDS is rare. We present the third case of CDH with clinical features of DDS and the same, rare Arg366His mutation in the WT1-gene, as reported in the other two known cases. This report provides additional evidence that WT1 mutations can result in diaphragmatic hernia.

Spinal stenosis with paraparesis in albright hereditary osteodystrophy. Case report and review of the literature.

We describe thoracic spinal stenosis with progressive myelopathy in association with Albright hereditary osteodystrophy (AHO) in a 12-year-old child with delayed diagnosis and review the relevant literature in order to identify the pathophysiological mechanism. The child was successfully treated by decompressive upper thoracic laminoplasty with full neurological recovery. The pathological changes of the skin also dissolved. Ten more cases of myelopathy and paraparesis in association with AHO, of whom two were children, could be found in the literature. Basically, two different causes for the spinal canal stenosis could be identified: abnormal ossifications of ligaments and congenital narrow spinal canal due to short vertebral pedicles. Awareness of structural spinal column changes in AHO is essential in order to appreciate the neurological symptoms of a beginning myelopathy before irreversible damage to the myelum occurs.

Expanding the genetic spectrum of Noonan syndrome.

BACKGROUND: The autosomal-dominant Noonan syndrome (MIM 163950) is characterized by short stature, typical facial dysmorphology and heart defects. Noonan syndrome is genetically heterogeneous. Over the last few years, germline mutations in four genes have been found in people with clinical signs of Noonan syndrome, accounting for approximately 65% of cases. All four genes encode proteins involved in the Ras-mitogen-activated protein kinase pathway and result in upregulation of this pathway. Recently, more data on final height after long-term growth hormone (GH) therapy has become available that shows its effectiveness in increasing final height for individuals with Noonan syndrome. CONCLUSIONS: The genetics underlying Noonan syndrome has been partially clarified over the last 5 years and further findings will undoubtedly be reported in the next few years. GH therapy has been used to treat patients with Noonan syndrome for approximately 15 years and is effective in improving adult height in affected children.

Benign course after acute high dose levothyroxine intoxication in a 3-year-old boy.

Acute ingestion of thyroid hormone preparations is a common intoxication, with 181 cases in children <12 yr in 2009 in the Netherlands, but generally has a mild course. However, some reports show that even low dosages may cause serious events such as seizures, thyroid storm and coma. We report a 3 yr old boy case with an acute intoxication with high dose levothyroxine (0.5 mg/kg). We describe the proper management of levothyroxine intoxication in children. A 3-year-old boy with no notable medical history ingested sixty tablets of levothyroxine 150 µg. His vital-signs were normal and the only symptom during admission was a tachycardia the following day. Laboratory data showed elevated T3, fT3 and fT4 levels; and decrease TSH levels. He was treated prophylactically and therapeutically with activated charcoal and propranolol. Despite very high levels, his clinical symptoms were relatively mild. After clinical follow-up for 3 d he was discharged. We propose that children with thyroid hormone intoxication with either a levothyroxine dose >0.1 g/kg, a short interval since ingestion, symptomatic presentation, and/or a fT4 >100 pmol/l should be monitored in the hospital during at least 48-72 h post-ingestion and on an outpatient basis for 14 d.

Absence of increased height velocity in the first year of life in untreated children with simple virilizing congenital adrenal hyperplasia.

CONTEXT: In congenital adrenal hyperplasia (CAH), elevation of adrenal androgens leads to accelerated growth and bone maturation with compromised adult height. OBJECTIVE/PATIENTS: The objective of the study was to analyze retrospectively early growth and bone maturation in 17 untreated simple virilizing (SV) CAH patients. SETTING: The study was conducted at Radboud University Nijmegen Medical Centre. INTERVENTIONS: Growth data were collected until time of diagnosis. Height was expressed as height sd score and corrected for target height. Bone maturation was determined and expressed as bone age acceleration. MAIN OUTCOME MEASURES: Growth pattern and bone maturation were measured before the diagnosis. RESULTS: In the term group (n = 11), there was no increase in height sd score and corrected for target height in the first year of life [-0.1 sd/yr; 95% confidence interval (CI) -0.5, 0.3] with a consecutive significant (P < 0.001) increase up to 0.9 sd/yr (95% CI 0.7, 1.0). In the premature group (n = 3), there was a catch-up growth of 1.6 sd/yr (95% CI 0.9, 2.3) in the first year followed by a growth of 1.1 sd/yr (95% CI 0.9, 1.5) in the following years. There was a positive linear correlation between bone age acceleration and age of diagnosis (r = 0.8). CONCLUSIONS: Height velocity and bone maturation are not increased in untreated children with mild forms of SV CAH in the first year of life. After this period there is a progressive increase in height velocity and bone maturation in strong relation to the duration of androgen exposition. This observation has implications for the dose of glucocorticoids to be used in SV CAH patients in the first year of life.

High serum levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I) during high-dose GH treatment in short children born small for gestational age.

CONTEXT: Epidemiological studies have indicated that high serum levels of GH and IGF-I are associated with long-term risks. OBJECTIVE: The objective of the study was to evaluate the changes in serum levels of GH during overnight profiles, IGF-I, and IGF binding protein 3 (IGFBP-3) in short small for gestational age (SGA) children during GH treatment with two doses. PATIENTS: Thirty-six prepubertal short SGA children were the subjects of this study. INTERVENTION: Subjects received 1 (group A) or 2 (group B) mg GH/m(2).d. MAIN OUTCOME MEASURES: At baseline and after 6 months of GH treatment, overnight GH profiles were performed, and serum IGF-I and IGFBP-3 levels were measured. RESULTS: After 6 months, group B had significantly higher GH levels during the profile (mean, maximum, and area under the curve above zero line) than group A (P < 0.009). In group B, maximum GH levels increased from 43.9-161 mU/liter (P < 0.0002), and in group A, from 57.2-104 mU/liter (P = 0.002). During the profile (i.e. 12 h per day), children of group B had mean GH levels of 64.4 vs. 34.8 mU/liter in group A (P = 0.001). The IGF-I and IGF-I to IGFBP-3 ratio sd scores increased significantly in both groups, but were higher in group B than A [1.5 vs. 0.2 (P = 0.002) and 1.4 vs. 0.3 (P = 0.007), respectively]. In group B, 74% of the children had IGF-I levels in the highest quintile during GH treatment compared with 19% in group A. CONCLUSION: Our study shows that high-dose GH treatment in short SGA children results in high serum GH and IGF-I levels in most children. We recommend monitoring IGF-I levels during GH therapy to ensure that these remain within the normal range.

Insights into the biochemical and genetic basis of glucokinase activation from naturally occurring hypoglycemia mutations.

Glucokinase (GCK) is a key regulatory enzyme in the pancreatic beta-cell and catalyzes the rate-limiting step for beta-cell glucose metabolism. We report two novel GCK mutations (T65I and W99R) that have arisen de novo in two families with familial hypoglycemia. Insulin levels, although inappropriately high for the degree of hypoglycemia, remain regulated by fluctuations in glycemia, and pancreatic histology was normal. These mutations are within the recently identified heterotropic allosteric activator site in the theoretical model of human beta-cell glucokinase. Functional analysis of the purified recombinant glutathionyl S-transferase fusion proteins of T65I and W99R GCK revealed that the kinetic changes result in a relative increased activity index (a measure of the enzyme's phosphorylating potential) of 9.81 and 6.36, respectively, compared with wild-type. The predicted thresholds for glucose-stimulated insulin release using mathematical modeling were 3.1 (T65I) and 2.8 (W99R) mmol/l, which were in line with the patients' fasting glucose. In conclusion, we have identified two novel spontaneous GCK-activating mutations whose clinical phenotype clearly differs from mutations in ATP-sensitive K(+) channel genes. In vitro studies confirm the validity of structural and functional models of GCK and the putative allosteric activator site, which is a potential drug target for the treatment of type 2 diabetes.

The relationship between clinical severity of Noonan's syndrome and growth, growth hormone (GH) secretion and response to GH treatment.

Short stature is one of the major features of Noonan's syndrome (NS). In a multicentre trial of growth hormone (GH) therapy in 25 children with NS, we observed a large inter-individual variation in first-year response to GH treatment. This suggested that subgroups might exist in NS that differ in either endogenous GH status or responsiveness to GH therapy. We therefore related growth, GH secretion and 2 years response to GH treatment to subtypes of phenotypic expression of NS. Twelve patients were moderately affected and 13 had a severe clinical phenotype of NS. The variability in phenotype did not correlate with significant differences in intra-uterine growth, infancy growth or childhood growth, and response to GH treatment. However, the variability in phenotype severity did account for striking differences in endogenous GH secretion.

Cancer risk in patients with Noonan syndrome carrying a PTPN11 mutation.

Noonan syndrome (NS) is characterized by short stature, facial dysmorphisms and congenital heart defects. PTPN11 mutations are the most common cause of NS. Patients with NS have a predisposition for leukemia and certain solid tumors. Data on the incidence of malignancies in NS are lacking. Our objective was to estimate the cancer risk and spectrum in patients with NS carrying a PTPN11 mutation. In addition, we have investigated whether specific PTPN11 mutations result in an increased malignancy risk. We have performed a cohort study among 297 Dutch NS patients with a PTPN11 mutation (mean age 18 years). The cancer histories were collected from the referral forms for DNA diagnostics, and by consulting the Dutch national registry of pathology and the Netherlands Cancer Registry. The reported frequencies of cancer among NS patients were compared with the expected frequencies using population-based incidence rates. In total, 12 patients with NS developed a malignancy, providing a cumulative risk for developing cancer of 23% (95% confidence interval (CI), 8-38%) up to age 55 years, which represents a 3.5-fold (95% CI, 2.0-5.9) increased risk compared with that in the general population. Hematological malignancies occurred most frequently. Two malignancies, not previously observed in NS, were found: a malignant mastocytosis and malignant epithelioid angiosarcoma. No correlation was found between specific PTPN11 mutations and cancer occurrence. In conclusion, this study provides first evidence of an increased risk of cancer in patients with NS and a PTPN11 mutation, compared with that in the general population. Our data do not warrant specific cancer surveillance.

Growth hormone producing prolactinoma in juvenile cystinosis: a simple coincidence?

Juvenile cystinosis was diagnosed in a patient who presented with severe headache attacks and photophobia. Treatment with oral cysteamine and topical cysteamine eye drops was started. One-and-a-half years later, he developed unilateral gynecomastia and elevated prolactin and growth hormone levels. A pituitary macroprolactinoma was discovered and successfully treated with the dopamine agonist cabergoline. Increased serum growth hormone levels were attributed to enhanced growth hormone production by the prolactinoma and somatostatin inhibition by cysteamine. Although the occurrence of prolactinoma in this patient could be a simple coincidence, it might also be a rare yet unrecognised complication of cystinosis.

Genotypic and phenotypic characterization of Noonan syndrome: new data and review of the literature.

Noonan syndrome (NS) is an autosomal dominant disorder, characterized by short stature, minor facial anomalies, and congenital heart defects. In approximately 50% of cases the condition is caused by missense mutations in the PTPN11 gene on chromosome 12, resulting in a gain of function of the protein SHP-2. In this study, PTPN11 mutation analysis was performed in 170 NS patients. In 76 (45%) of them a mutation was identified. We report on the distribution of these mutations, as well as on genotype-phenotype relationships. The benefit of the NS scoring system developed by van der Burgt et al. [(1994); Am J Med Genet 53:187-191] is shown, among physicians who consequently based their diagnosis on the NS scoring system the percentage mutation positive subjects was 54%, whereas this percentage was only 39% among physicians who made less use of the scoring system. In two patients with some uncommon manifestations mutations were found in the C-SH2 domain, a region in which defects are not often identified in NS. A trend was observed in patients carrying the 922A --> G change (Asn308Asp) receiving normal education. In one patient with NS and mild juvenile myelomonocytic leukemia (JMML) the mutation 218C --> T (Thr73Ile) was found. This confirms previous findings indicating that individuals with NS with specific mutations in PTPN11 are at risk of developing JMML.

Genetics and variation in phenotype in Noonan syndrome.

Noonan syndrome is a well-known clinical entity comprising multiple congenital anomalies characterized by typical facial features, short stature and congenital heart defect. Approximately 50% of cases are sporadic. Familial cases are generally autosomal dominant. In 2001 a gene responsible for Noonan syndrome, PTPN11, encoding for the non-receptor protein tyrosine phosphatase SHP-2, was identified. Mutation analysis of the PTPN11 gene was carried out in Nijmegen in 150 patients with Noonan syndrome. Mutations were found in 68 patients (45%), the most common being A922G in exon 8. In exon 4 a mutation was found that encoded the C-SH2 domain of the PTPN11 gene in two unique patients who shared some uncommon features. A 218C-->T mutation was found in exon 3 in one patient with Noonan syndrome and mild juvenile myelomonocytic leukaemia.

Quantitative calcaneal ultrasound parameters and bone mineral density at final height in girls treated with depot gonadotrophin-releasing hormone agonist for central precocious puberty or idiopathic short stature.

UNLABELLED: To evaluate the effect of gonadotrophin-releasing hormone (GnRH) agonist treatment on bone quality at final height, we studied girls with central precocious puberty (CPP) and with idiopathic short stature (ISS). A total of 25 Caucasian girls were included: group A (n=14) with idiopathic CPP (mean age at start 7.4 years) and group B (n=11) with ISS (mean age at start 11.7 years). Treatment duration was 3.8 and 1.7 years respectively. The quantitative ultrasound parameters (QUS) broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at the calcaneus (UBIS 3000 device). Lumbar spine bone mineral density (BMD; L2-L4) was measured by dual energy X-ray absorptiometry (DXA) (Hologic QDR1000). Measurements were performed at final height and expressed as Z-scores corrected for bone age. Mean Z-scores of QUS parameters, areal BMD and volumetric BMD (BMDvol) were above -1 in both groups (group A: BUA Z-score -0.21, SOS Z-score -0.29, BMD Z-score 0.02, BMDvol Z-score 0.05, group B: BUA Z-score -0.93, SOS Z-score -0.40, BMD Z-score -0.86, BMDvol Z-score -0.68), although mean Z-scores of BUA and areal BMD in group B were significantly different from zero (P=0.03 and P=0.02 respectively). Mean Z-score BMDvol was not significantly different from zero (P=0.05), we found no significant difference between the groups for BMDvol (P=0.13). CONCLUSION: Although quantitative ultrasound parameters parameters and bone mineral density were normal in girls with central precocious puberty at final height after gonadotrophin-releasing hormone agonist treatment, mean Z-score for broadband ultrasound attenuation and areal bone mineral density were significantly different from zero and mean Z-score for volumetric bone mineral density was (just) not significantly different from zero in idiopathic short stature girls with normal puberty treated with gonadotrophin-releasing hormone agonists. Therefore we cannot say that this treatment is safe in these girls with regard to bone health.