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Biomedical subjects

R Pfäffle

Publications and source records attributed to R Pfäffle.

18 recordsLinked to original sources
PubMed2006

Clinical and functional characteristics of the human Arg59Ter insulin-like growth factor i receptor (IGF1R) mutation: implications for a gene dosage effect of the human IGF1R.

CONTEXT: Signaling via the IGF-I receptor (IGF-IR) is crucial for normal prenatal and postnatal growth. The heterozygous IGF-IR mutation Arg59Ter resulted in reduced IGF-IR expression and represents haploinsufficiency of the human IGF1R gene. OBJECTIVE: We studied clinical and in vitro aspects of a human IGF1R gene dosage effect. We provide detailed clinical data on the two half-brothers and their mother with the Arg59Ter mutation. Arg59Ter and control fibroblasts were examined for functionality of IGF-I and insulin-stimulated receptor phosphorylation and signal transduction. RESULTS: The two brothers presented with primary microcephaly, mild mental retardation, and intrauterine as well as postnatal growth deficits. After GH therapy (30 microg/kg.d) for 24 months, the growth deficit in the propositus decreased by +1.0 sd. There was no clinical evidence for impaired glucose tolerance or hypoglycemia in all Arg59Ter subjects. In vitro, IGF-IR-deficient Arg59Ter cells expressed less IGF-IR and unchanged insulin receptor (IR) protein. Receptor autophosphorylation and phosphorylation of downstream protein kinase B/Akt exhibited resistance to IGF-I but showed an augmented response to insulin in Arg59Ter cells. Decreased IGF-IR content was accompanied by a reduction of IGF-IR/IR receptor hybrids, and therefore, increased levels of IR/IR homodimers probably explain increased insulin-stimulated receptor autophosphorylation and Akt phosphorylation. CONCLUSIONS: In vivo and in vitro IGF-I resistance in Arg59Ter subjects and fibroblasts indicates a human IGF1R gene dosage effect involving not only the IGF-IR, but also IGF-IR/IR hybrids. The abundance of both the IGF-IR protein and IGF-IR/IR hybrid receptors may have an impact on human growth, organ function, and glucose metabolism.

Body Weight↗
PubMed2005

A new heterozygous mutation of the FOXL2 gene is associated with a large ovarian cyst and ovarian dysfunction in an adolescent girl with blepharophimosis/ptosis/epicanthus inversus syndrome.

Blepharophimosis/ptosis/epicanthus inversus syndrome (BPES), an autosomal dominant syndrome in which eyelid malformation is associated with (type I BPES) or without premature ovarian failure (type II BPES). Mutations of a putative winged helix/forkhead transcription factor FOXL2 account for both types of BPES. We report on a 16-year-old adolescent girl with blepharophimosis and ptosis. Subsequently she developed oligomenorrhea, secondary amenorrhea for 6 months, and an extremely large cyst of one ovary. The cyst contained 8 l of cyst fluid and histopathology displayed a large corpus luteum cyst. Following laparotomy, gonadotropin levels were elevated (LH 17.2 U/l, FSH 29.4 U/l) and estradiol levels decreased (67 pmol/l). Because of clinical aspects of BPES and abnormal ovarian function we suspected a mutation of her FOXL2 gene and found a new in-frame mutation (904_939dup36) on one allele, leading to a 12 alanine expansion within the polyalanine domain. We conclude that the FOXL2 mutation 904_939dup36 may account not only for blepharophimosis and ptosis but also for ovarian dysfunction and growth of the large corpus luteum cyst. In contrast to known FOXL2 mutations with polyalanine expansions and association with BPES type II, clinical aspects of our girl may indicate some degree of ovarian dysfunction that might finally lead to BPES type I with premature ovarian failure.

Adolescent↗
PubMed2002

Adrenocorticotrope deficiency with clinical evidence for late onset in combined pituitary hormone deficiency caused by a homozygous 301-302delAG mutation of the PROP1 gene.

Combined pituitary hormone deficiency (CPHD) can be caused by mutation of the pituitary transcription factors POU1F1 or PROP1. More recently mutations in the HESX1, the LHX3 and LHX4 transcription factor genes have also been described as a cause in patients with CPHD. In most patients the disorder is characterized by an impaired production of GH, TSH, PRL and gonadotropins. In some cases of CPHD adrenocorticotropin deficiency is also present. We report the progressive CPHD and its molecular etiology in a woman with CPHD presenting with first symptoms of ACTH/cortisol deficiency at the age of 48 years. The 49 year old patient's initial symptoms were growth retardation at the age of 2 years and symptoms of hypothyroidism at the age of 5 years. The patient never entered puberty spontaneously. No familial history of delayed puberty, growth retardation or other symptoms of CPHD were present. At the age of 48 years the patient presented with the first symptoms of hypocortisolism such as recurring hypoglycaemias and hyponatriaemia with coma. Cortisol, ACTH, TSH, fT3, fT4 and GH as well as LH, FSH and PRL were measured in basal conditions. GH, cortisol and ACTH were also measured in response to an Insulin Tolerance Test. Molecular analysis was performed by PCR amplification and sequencing of exon 1-3 of the PROP1 gene. The patient had insufficiencies of TSH, LH, FSH and GH. PRL was normal. Serum cortisol was low and basal ACTH was normal. However, there were no responses of cortisol, ACTH and GH to hypoglycaemia. Magnetic resonance imaging showed a hypoplastic anterior pituitary lobe. Direct sequencing revealed a homozygous 2 base-pair deletion 301-302delAG in exon 2 of the PROP1 gene. This case suggests that in patients with CPHD ACTH producing cells may be involved at a rather late age.

Adrenocorticotropic Hormone↗
PubMed2002

Familial combined pituitary hormone deficiency caused by PROP-1 gene mutation. Growth patterns and MRI studies in untreated subjects.

BACKGROUND: Mutations of the prophet of PIT-1 (PROP-1), a paired-like homeodomain transcription factor which is responsible for early embryonic pituitary development, have recently been reported as a cause of combined pituitary hormone deficiency. METHODS: We describe the phenotype, long-term auxological data and MRI findings in two families with 4 affected members, all of whom have a mutation of the PROP-1 gene. GH, TSH, PRL, LH and FSH were completely deficient in all patients. RESULTS: ACTH deficiency was not diagnosed until the 3rd or 4th decades of life. Pituitary MRI showed an empty sella in 2 subjects, but unspecific tissue accumulation resembling a pituitary mass lesion in another patient. The affected boy from family II who was continuously treated with all the necessary hormones reached the familial target height. However, the 3 subjects in family I were only treated sporadically (GH treatment lasting from 1 to 3 years). CONCLUSION: Despite this insufficient therapy, final height was in the lower normal range. Longitudinal growth continued up to the age of 40 years in these subjects.

Adolescent↗
PubMed2001

A new C-terminal located mutation (V272ter) in the PIT-1 gene manifesting with severe congenital hypothyroidism. Possible functionality of the PIT-1 C-terminus.

OBJECTIVE: We describe a newborn with clinical signs of severe hypothyroidism and combined pituitary hormone deficiency due to a new mutation in the PIT-1 gene. PATIENT AND METHODS: Endocrine stimulation test revealed a deficiency for PRL, TSH and GH, suggesting a defect in the pituitary transcription factor PIT-1. Genetic analysis of the PIT-1 gene was performed by exon-specific PCR, followed by SSCP mutation screening and DNA sequencing of the abnormal migrating fragments. RESULTS: DNA sequencing revealed a new mutation (V272ter) in direct neighborhood to a known mutational hot spot (R271W) in the C-terminal part of the PIT-1 molecule. CONCLUSIONS: Whereas the R271W mutation has a dominant negative effect on the mutant protein, the newly described mutation is inherited in an autosomal-recessive way. The biological consequences of these two different mutations are discussed.

Base Sequence↗
PubMed2000

Combined pituitary hormone deficiency and pituitary hypoplasia due to a mutation of the Pit-1 gene.

Several mutations of the pituitary-specific transcription factor Pit-1 have been identified. We describe a girl with a mutation of the Pit-1 gene leading to a complete lack of GH, TSH and prolactin and a marked hypoplasia of the anterior pituitary gland. The patient had a homozygous nonsense-mutation at position 172 (CGA to TGA), converting arginine into a stop codon, leading to an early termination of protein translation. During the infancy period the girl had very conspicuous symptoms of hypothyroidism and the diagnosis of thyroid insufficiency preceded the diagnosis of GH-deficiency by 1.5 years. Treatment with thyroxine and GH resulted in excellent catch-up growth.

Body Height↗
PubMed2000

Idiopathic growth hormone deficiency: a vanishing diagnosis?

Some non-organic causes for growth hormone (GH) deficiency (GHD) can be attributed to genetic defects within the hypothalamo-pituitary axis. Using modern molecular biology techniques micromutations within the GH and GH-releasing hormone receptor genes have been detected as a rare cause of isolated GHD. Combined pituitary hormone deficiencies (CPHD), on the other hand, are associated with defects that manifest during the organogenesis of the anterior pituitary gland. In recent years an increasing number of patients with CPHD has been reported, showing mutations within pituitary transcription factors Pit-1, Prop-1 and HesX1. Such defects can be observed with different frequencies in patients. Some disorders, such as CPHD due to Pit-1 mutations, display a hormonal phenotype that seems more or less invariable. In most other forms of genetic CPHD both the combination and severity of anterior pituitary hormone deficiencies vary considerably. Ongoing research concentrates on factors involved in the differentiation and proliferation of cells that belong to the hypothalamo-pituitary growth axis. As not every possible candidate turns out to be a frequent cause of GHD or CPHD in humans, it will be many more years before the term 'idiopathic' becomes a vanishing attribute to the clinical diagnosis of pituitary insufficiency.

Animals↗
PubMed1999

Seminoma in a 31-year-old patient on long-term growth hormone therapy.

We describe a Caucasian male patient aged 31, who was referred to the Institute of Reproductive Medicine because of infertility and androgen deficiency and in whom we incidentally diagnosed a unilateral testicular tumor. The patient had received growth hormone (GH) since the age of 8 years. One case presenting with testicular neoplasm under growth hormone substitution has been described previously. In conclusion, it cannot be ruled out that GH treatment may be involved in the pathogenesis of germ cell tumor development. Special care should be exercised when patients with a history of maldescended testes require GH substitution. This care should include regular testicular ultrasonography at e.g. half-yearly intervals since sonography may detect testicular tumors long before they become clinically apparent.

Adult↗
PubMed1999

Neonatal diabetes mellitus with hypergalactosemia.

We report the case of a male, small-for-gestational-age newborn who presented with failure to thrive, severe fluctuation of blood glucose concentrations, and increased serum concentrations of galactose. The infant responded well to a lactose-free diet supplemented with fructose, inulin and corn starch. The metabolic disorder disappeared within 6 months. The transient course, and results of a molecular analysis of the glucose transporter 2 (Glut2) gene seem to rule out Fanconi-Bickel syndrome.

Diabetes Mellitus↗
PubMed1998

The hypothalamic-pituitary-adrenal axis in preterm infants weighing < or = 1250 g: association with perinatal data and chronic lung disease.

The hypothalamic-pituitary-adrenal axis (HPA) was examined in 34 ventilated preterm infants weighing < or = 1250 g during the first week of life to evaluate the association between adrenal suppression and subsequent chronic lung disease. The second aim of the study was to detect perinatal and clinical differences between the infants with and without persistent suppression of the HPA after completion of dexamethasone treatment for chronic lung disease. To evaluate the HPA, the corticotropin-releasing hormone stimulation test was performed, and the cortisol and adrenocorticotropic hormone (ACTH) levels were measured by radioimmunoassay. No association could be found between the synthesis of cortisol and ACTH at the end of the first week of life and the development of chronic lung disease. After treatment with dexamethasone, baseline cortisol levels < 138 nmol l(-1) were found in 12 infants (46.2%), 8 of whom (30.8%) had cortisol values below 83 nmol l(-1). The perinatal data of these patients did not differ from infants without HPA suppression. However, the infants with cortisol levels < 83 nmol l(-1) after dexamethasone showed a significantly shorter need for mechanical ventilation and supplemental oxygen (p < 0.01) and a lower incidence of chronic lung disease (p < 0.05).

Chronic Disease↗
PubMed1997

Combined pituitary deficiencies of growth hormone, thyroid stimulating hormone and prolactin due to Pit-1 gene mutation: a case report.

UNLABELLED: A child exhibited postnatal obstipation and icterus together with severe growth failure during the 1st year of life, a small facial skull and a prominent forehead. Endocrine work-up established the diagnosis of combined pituitary deficiencies of growth hormone, TSH and prolactin. Subsequently, the Pit-1 gene was analysed in the patient and both parents. A single point mutation was detected in exon 6 of the child: a C to G transversion on one allele, causing arginine in position 271 to be substituted by tryptophan (R271 W). This position is known as a "hot spot" for mutations. The inheritance is autosomal-dominant, as the mutated gene product interferes with DNA-binding of the wild-type protein. In contrast, other mutations in the PIT-1 gene are inherited in an autosomal-recessive mode. CONCLUSION: Diagnosing Pit-1 gene mutations as a rare cause of combined pituitary deficiency is important both for genetic counselling as well as for predicting the future course in the patient (spontaneous puberty, no glucocorticoid substitution necessary during stress periods).

Arginine↗
PubMed1996

Pit-1: clinical aspects.

Pit-1 is a transcription factor which is expressed in the somatotrope, lactotrope, and thyrotrope cell population of the anterior pituitary gland from early fetal development throughout life. Mutations in the Pit-1 gene result in insufficient expression of this factor, accounting for a form of combined pituitary hormone deficiency for growth hormone (GH), prolactin, and thyroid-stimulating hormone. Clinical presentation at diagnosis can be variable, although all forms finally result in severe growth retardation due to GH deficiency and hypothyroidism. The clinical variability is due to other factors than the exact location of the mutation; however, the type of inheritance seems to correlate well with the genotype. Early detection of Pit-1 abnormalities might prevent the sequelae associated with some early and severe presentations of this disorder.

Animals↗
PubMed1993

[Glucose homeostasis in cystic fibrosis. Oral glucose tolerance test in comparison with formula administration].

BACKGROUND: Glucose tolerance is often impaired in Cystic Fibrosis. The impact of this condition on enteral nutritional support in case of malnourishment remains to be studied. METHOD: In this study the glucose-, C-peptide- and insulin-responses to an OGTT and a standard enteral formula load were investigated in 19 non-diabetic CF-patients. Each test was performed with a carbohydrate load of 1.75 g/kg bodyweight. RESULTS: 11 patients had a normal OGTT (Group I) and 8 had an impaired glucose tolerance (Group II). After the formula load the glucose concentrations were significantly lower than after the OGTT at 30, 60, and 90 min in both groups and at 120 min in group II only. In group II the glucose values exceeded 6.7 mmol/l at 120 min after both OGTT and formula load and were significantly higher than in group I. The food glycaemic index, a parameter for comparison of glucose response to different diets was calculated. It ranged from 30 to 80% in both groups. An increased C-peptide- and insulin-secretion was found in patients with impaired glucose tolerance. CONCLUSIONS: The condition of impaired glucose tolerance must be considered for enteral hyperalimentation of Cystic Fibrosis-patients. The selection of formulas for nutritional support should be based on the calculation of the Food Glycemic Index because of its high interindividual variability.

Adolescent↗
PubMedDate not supplied

Decreased factor XIII activity during severe Henoch-Schoenlein purpura -- does it play a role?

BACKGROUND: In patients with Henoch-Schoenlein purpura (HSP), particularly with severe gastrointestinal symptoms, an associated decrease of plasma factor XIII has been observed. PATIENT: The authors report a case of HSP in a boy and describe the development of factor XIII activities throughout the course of the disease. Every relapse of severe gastrointestinal manifestation was associated with a decrease of factor XIII. No improvement was seen after treatment with prednisone. The symptoms resolved each time factor XIII concentrate was administered. With the return of factor XIII to normal values eight weeks after admission abdominal symptoms ceased. CONCLUSION: The documented course supports the hypothesis that factor XIII activity correlates well with the severity of abdominal symptoms. Measuring factor XIII activity helps to identify those patients with severe gastrointestinal manifestation who may benefit from substitution therapy.

Child↗
PubMedDate not supplied

[Function of the hypothalamo-hypophyseal-adrenal axis to corticotropin-releasing hormone test in premature infants with bronchopulmonary dysplasia].

BACKGROUND: The purpose of this prospective study was to examine the hypothalamic-pituitary-adrenal axis using the corticotropin-releasing hormone stimulation test in 24 preterm infants (mean gestational age 27.4 +/- 1.4 weeks, mean birth weight 997 +/- 166 g) with bronchopulmonary dysplasia after completion of dexamethasone treatment. METHODS: The CRH stimulation test was performed before and two days after the course of dexamethasone therapy in a dosage of 1 microgram/kg body weight. Blood samples were obtained before and 30 minutes after application of CRH. The blood values for cortisol and ACTH were measured by radioimmunoassay. RESULTS: The mean basal cortisol level was significantly reduced from 338 +/- 283 nmol/l before dexamethasone treatment to 153 +/- 102 nmol/l after dexamethasone therapy. The site of HPA suppression was located to the pituitary gland as the mean basal ACTH level dropped from 9.5 +/- 5.2 pmol/l to 5.6 +/- 2.0 pmol/l after the dexamethasone course. In 9 infants there was only an insufficient increase of cortisol level after application of CRH as a possible sign of a reduced adrenal response. The patients with HPA-suppression did not differ in clinical aspects from infants without suppression of the HPA. CONCLUSION: The results demonstrate a significant suppression of the adrenal and pituitary gland in very low birth weight infants with bronchopulmonary dysplasia after dexamethasone treatment. Before stressful situations like surgery we therefore recommend an investigation of the HPA.

Adrenocorticotropic Hormone↗