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Laron dwarfism and non-insulin-dependent diabetes mellitus in the Hnf-1alpha knockout mouse.

Mice deficient in hepatocyte nuclear factor 1 alpha (HNF-1alpha) were produced by use of the Cre-loxP recombination system. HNF-1alpha-null mice are viable but sterile and exhibit a phenotype reminiscent of both Laron-type dwarfism and non-insulin-dependent diabetes mellitus (NIDDM). In contrast to an earlier HNF-1alpha-null mouse line that had been produced by use of standard gene disruption methodology (M. Pontoglio, J. Barra, M. Hadchouel, A. Doyen, C. Kress, J. P. Bach, C. Babinet, and M. Yaniv, Cell 84:575-585, 1996), these mice exhibited no increased mortality and only minimal renal dysfunction during the first 6 months of development. Both dwarfism and NIDDM are most likely due to the loss of expression of insulin-like growth factor I (IGF-I) and lower levels of insulin, resulting in stunted growth and elevated serum glucose levels, respectively. These results confirm the functional significance of the HNF-1alpha regulatory elements that had previously been shown to reside in the promoter regions of both the IGF-I and the insulin genes.

Animals↗

Ultrasonic diagnosis of thanatophoric dwarfism in utero.

There are several types of short-limbed neonatal dwarfism. Before the delineation of thanatophoric dwarfism many dwarfs who died early in infancy were labeled "achondroplastic." Intrauterine radiological diagnosis is possible and the clinician may be alerted to the possibility of the condition by noting short squat limbs with a relatively large head on ultrasound examination, especially in cases of hydramnios.

Adult↗

Thanatophoric dwarfism. Two case reports and survey of the literature.

Thanatophoric dwarfism is a severe form of short-limbed dwarfism in which cardiorespiratory failure uniformly results in death in the neonatal period. Its radiographic features include markedly flattened vertebral bodies with a typical U-shaped deformity, a flat squat pelvis, and short, bowed extremities with flaring and irregularity of the metaphyses. These characteristic features distinguish this entity from the two other most commonly confused congenital short-limbed forms of dwarism--achondroplasia and achondrogenesis. The distinctions are discussed in the text.

Achondroplasia↗

Relationship between sleep stage IV deficit and reversible HGH deficiency in psychosocial dwarfism.

Polygraphic sleep recordings were done in four children with psychosocial dwarfism. The first recordings, performed within the first days after hospitalization, exhibited a gross deficit of stage IV sleep and a decrease of the durations of slow wave sleep episodes (SWS = stage III and IV). The second recordings were performed after several wk (3-15) in the new environment, during the growth recovery period. A clear improvement of sleep quality was observed, namely an increase of stage IV amounts. In two of the four patients, hGH release was studied by means of the ornithine test. A low response was found in the first (2) days of hospitalization whereas normal response was observed during the recovery period suggesting a partial and reversible hGH deficiency. A simultaneous recovery of both stage IV sleep and the growth rate was observed in the four patients. These data suggest that sleep disturbances are strongly linked to growth failure in psychosocial dwarfism.

Child, Preschool↗

Phenotype and genetic analysis of a syndrome caused by an inactivating mutation in the growth hormone-releasing hormone receptor: Dwarfism of Sindh.

We report, in detail, a new form of familial dwarfism, including its phenotypic features, hormonal profile, and molecular basis. Following a newspaper report of severe dwarfism in two villages in the province of Sindh, Pakistan, we organized an expedition to study its clinical, genetic, and molecular characteristics. We identified 18 dwarfs (15 male, 3 female), all members of a consanguineous kindred, ranging in age from newborn to 28 yr. Mean height was 7.2 SD below the norm, with mean adult heights of 130 cm for males and 113.5 cm for females. Body proportions and habitus were normal; but head circumference was 4.1 SD, and blood pressure approximately 3 SD below the norm. There was no dysmorphism, no microphallus, and no history of hypoglycemia. Serum GH did not respond to provocative stimuli (GHRH, L-dopa, or clonidine). Insulin-like growth factor I (IGF-I) and IGF-binding protein 3 were low (5.2 +/- 2.0 ng/mL and 0.42 +/- 0.13 microg/mL, respectively; mean +/- SD) but rose normally with GH treatment. One affected, dwarfed couple had a son, demonstrating fertility in both sexes. Clinical and endocrinological evidence suggested isolated GH deficiency with a recessive inheritance pattern. The GH-N gene was found to be intact. Linkage analysis of microsatellite chromosomal markers near other candidate genes yielded a high LOD score (6.26) for the GHRH receptor (GHRH-R) locus. DNA sequencing revealed a nonsense mutation (Glu50-->Stop) in the extracellular domain of the GHRH-R. This mutation predicts a severely truncated GHRH-R; it is identical to that recently reported in four patients from two other families. Inheritance is autosomal recessive (chromosome 7p) with a high degree of penetrance. Relatives heterozygous for the mutation had moderately decreased IGF-I levels and slightly blunted GH responses to GHRH and L-dopa, but they showed only minimal or no height deficit. This syndrome represents the human homologue of the little (lit/lit) mouse and closely resembles its phenotype. It demonstrates the absolute requirement of GHRH signaling for pituitary GH secretion and postnatal growth in humans, and its relatively minor (but discernible) biological importance in extrapituitary sites. The syndrome is distinct from other forms of GH deficiency with respect to microcephaly, asymptomatic hypotension, and absence of features such as facial dysplasia, significant truncal obesity, microphallus, or hypoglycemia. Its discovery raises the possibility of milder mutations in the GHRH-R gene as potential causes for partial GH insufficiency and idiopathic short stature.

Adolescent↗

Adaptive stress response in segmental progeria resembles long-lived dwarfism and calorie restriction in mice.

How congenital defects causing genome instability can result in the pleiotropic symptoms reminiscent of aging but in a segmental and accelerated fashion remains largely unknown. Most segmental progerias are associated with accelerated fibroblast senescence, suggesting that cellular senescence is a likely contributing mechanism. Contrary to expectations, neither accelerated senescence nor acute oxidative stress hypersensitivity was detected in primary fibroblast or erythroblast cultures from multiple progeroid mouse models for defects in the nucleotide excision DNA repair pathway, which share premature aging features including postnatal growth retardation, cerebellar ataxia, and death before weaning. Instead, we report a prominent phenotypic overlap with long-lived dwarfism and calorie restriction during postnatal development (2 wk of age), including reduced size, reduced body temperature, hypoglycemia, and perturbation of the growth hormone/insulin-like growth factor 1 neuroendocrine axis. These symptoms were also present at 2 wk of age in a novel progeroid nucleotide excision repair-deficient mouse model (XPD(G602D/R722W)/XPA(-/-)) that survived weaning with high penetrance. However, despite persistent cachectic dwarfism, blood glucose and serum insulin-like growth factor 1 levels returned to normal by 10 wk, with hypoglycemia reappearing near premature death at 5 mo of age. These data strongly suggest changes in energy metabolism as part of an adaptive response during the stressful period of postnatal growth. Interestingly, a similar perturbation of the postnatal growth axis was not detected in another progeroid mouse model, the double-strand DNA break repair deficient Ku80(-/-) mouse. Specific (but not all) types of genome instability may thus engage a conserved response to stress that evolved to cope with environmental pressures such as food shortage.

Aging↗

[A case of recessive dystrophic epidermolysis bullosa associated with dwarfism with special reference to pathophysiological role of growth hormone].

Epidermolysis bullosa is a group of disorders whose common primary feature is the formation of blisters following trivial trauma. Recessive dystrophic epidermolysis bullosa (RDEB), a subtype of epidermolysis bullosa, is frequently associated with growth retardation. This growth retardation has been reported to be caused by trophopathy following protein loss through skin lesions. Endocrine disorders as the cause of growth retardation in RDEB have not been clearly described. An 11-year-old female had a typical RDEB with dwarfism. Her height was 125 cm and weight was 21 kg, both of which were 2.5 SD below the average. The skin lesions were generalized and probably caused by undernourishment, infection, and blood loss through the skin. However, her serum albumin was at the lower normal limit, and the rapid turnover proteins were slightly decreased. Endocrinological examinations revealed that all the basal levels of pituitary, thyroid, and adrenal hormones were normal. Results of the exercise test, the insulin tolerance test, and the growth hormone-releasing factor test indicated the presence of hypothalamic disorder in secretion of growth hormone. This is the first report of RDEB in which hypothalamic disorder in growth hormone secretion was investigated. On the other hand, growth hormone is known to be involved in collagen metabolism, and a decrease in collagen fibrils and an increase in collagenase activities are found in the skin of RDEB. This implies that this hypothalamic disorder in growth hormone secretion may be involved in the pathophysiology of both dwarfism and the skin lesions in RDEB.

Child↗

Hypothalamic-pituitary functions in patients with idiopathic pituitary dwarfism.

To investigate hypothalamic-pituitary functions and the primary site of the lesion in idiopathic pituitary dwarfism, various pituitary function tests, especially the pituitary hormone responses to the hypophysiotropic hormones were studied in 23 patients with idiopathic pituitary dwarfism. A few cases showed slight responses of GH to GH stimulation tests. Gonadotropin deficiencies were most frequently noted among pituitary hormones. The basal levels and the responses of plasma LH and FSH to LH-RH test were diminished markedly in all of the cases except in 5 cases with isolated GH deficiency. Responses of LH and FSH to LH-RH improved markedly after a long term administration of LH-RH for a period of one month in 2 patients with gonadotropin deficiency. As to TSH axis, half of the cases accompanied hypothyroidism. However, the responses of TSH to TRH were normal in all of the cases regardless of the thyroid function. The basal levels and the responses of plasma cortisol and 11-deoxycortisol to the rapid metopirone test were also impaired in about half of the cases. Basal levels of plasma prolactin were normal in all of the cases and the responses of prolactin to TRH were normal in cases with normal thyroid function, but slightly delayed in cases with hypothyroidism. It is concluded from the above observations that the incidences of various pituitary hormone deficiencies were quite high in this disorder and hypophysiotropic hormone deficiencies may cause pituitary hormone deficiencies. Therefore, it is suggested that the primary site of the lesion in this disorder might be at the hypothalamus.

Adolescent↗

Optic hypoplasia with pituitary dwarfism (Kaplan-Grumbach-Hoyt syndrome, or DeMorsier syndrome).

A case of a 14-year-old boy with optic hypoplasia and pituitary dwarfism was presented. Eye Examination showed typical hypoplasia of the left optic nerve and mild hypoplasia of the right optic nerve. Except for dwarfism and nystagmus, the appearance of the patient was not unusual. Computed tomography revealed an enlargement of the suprachiasmatic cistern, and the presence of the septum pellucidum. The pituitary function tests revealed complete deficiency in GH, and poor or intermediate secretion in ACTH, TSH, PRL, LH and FSH. Urine volume and specific gravity were normal. Therapy with human growth hormone has been successful. It was indicated that hypopituitarism was probably of hypothalamic origin and early recognition of the syndrome is important in view of the possibility of treating growth retardation in some blind, or near blind children.

Adolescent↗

Dwarfism in a sabellid polychaete, a study of an interstitial species.

The anatomy and behavior of a species of the sabellid polychaete subfamily Fabricinae, is described. Mature individuals are virtually microscopic and represent the extreme degree of dwarfism apparently possible for a sabellid. Eggs are matured and liberated unilaterally, one at a time, from a single thoracic segment. Dwarfism in this species is essentially a cessation of body growth at a juvenile stage, accompanied by precocious sexual maturity, as an adaptation to persistent occupation of an interstitial detrital habitat.

Animals↗

Immunodeficient dwarfism in dogs: a model for neuroimmunomodulation.

This paper discusses the use of dogs as experimental models for neuroimmunomodulation and compares immunodeficient dwarfism in dogs to that in rodents. Immunodeficient dwarfism in dogs is reviewed including description of the clinical syndrome, immunologic characteristics, neuroendocrine abnormalities, thymus histopathology, and therapy.

Animals↗

Lower limb lengthening in turner dwarfism.

The aim of this study was to review our cases of lower limb lengthening to treat Turner dwarfism, and to speculate whether or not effective limb lengthening can be achieved in this rare condition. Twelve tibiae and 2 femora were lengthened in 6 patients using the Ilizarov method for the tibia and a gradual elongation nail for the femur. The mean age at the time of surgery was 19 years, and the patients were followed up for a minimum of 2 years. The average gain in the tibial and femoral length was 6.2 cm and 6.0 cm, respectively. The average healing index of tibia and femur was 1.9 and 1.7 months. The average tibia-to-femur ratio improved from 0.68 preoperatively to 0.81 postoperatively, and leg-trunk ratios improved from 0.88 to 0.99. Seven segments (50.0 percent) had completed the lengthening protocol without complications. Two segments (14.3 percent) had an intractable pin site infection requiring a pin exchange, and four segments (35.7 percent) had twelve complications (a nonunion at the distraction site, premature consolidation, Achilles tendon contractures and planovalgus). The overall rate of complications was 100 percent for each bone lengthened. All the patients showing a nonunion at the distraction site had a reduced bone mass, which was less than 65 percent of those of the age-matched normal population. Despite the complications, all patients were satisfied with the results, and lower limb lengthening in Turner Dwarfism believed to be a valid option. However, it may require careful management in a specialist unit in order to prevent complications during the lengthening procedure. In addition, the osteopenia associated with an estrogen deficiency leading to problems in consolidation is a difficult issue to address.

Adolescent↗

[Thanatophoric dwarfism (author's transl)].

Two cases of thanatophoric dwarfism, one associated with cloverleaf skull diagnosed in the uterus and complete with histological findings are reported. Differential diagnosis with respect to similar forms of dwarfism and the genetic problem are discussed.

Diagnosis, Differential↗

[Differentiation of achondroplasia and other similar genetic dwarfism by FGFR3 gene analysis].

OBJECTIVE: To study the gene mutation of Chinese patients with achondroplasia(ACH) and to set up a simple and rapid molecular diagnostic method to differentiate ACH from other similar genetic dwarfism. METHODS: The specific fragment of fibroblast growth factor receptor 3(FGFR3) transmembrane domain was amplified from dried blood spots of 21 patients with ACH and 6 suspicious patients with ACH by polymerase chain reaction, then mutation was screened and detected by restrictive enzyme analysis, single strand conformation polymorphism(SSCP) and denaturing gradient gel electrophoresis(DGGE). RESULTS: One out of 6 suspicious cases was ACH and 5 were pseudoachondroplasia(PSACH). Twenty-one out of 22 patients with ACH bore a G to A transition at nucleotide 1138 and 1 bore a G to C transversion at this same position. CONCLUSION: The nucleotide 1138 of FGFR3 gene is also the hotspot of mutation in Chinese patients with ACH. A simple and rapid molecular diagnostic method has been set up to differentiate ACH from other similar genetic dwarfism.

Achondroplasia↗

Adjustment and rehabilitation problems of children and adolescents with growth retardation. I. Familial dwarfism with high plasma immunoreactive human growth hormone.

Nine children and adolescents with the syndrome of familial dwarfism and high plasma immunoreactive human growth hormone were assessed by means of a battery of psychological tests, and they and their parents were interviewed with the aim of studying the problems of adjustment and rehabilitation in this group of patients. The group as a whole showed a lower-than-average intelligence quotient and a distinct deficiency in visuomotor functioning. Although this type of dwarf is well proportioned and without major malformations, his markedly small stature and limited physical endurance cause various problems, including those of mobility, clothing, and accommodation to public transportation and normal-sized furniture in school and at work. Psychological problems include intrafamily relationships and the attitudes encountered in school, in social situations and at places of employment. It is concluded that these patients need the specialized counseling of a centralized rehabilitation center which offers a combined program of medical care, psychological support and assistance with such problems as schooling, choice of occupation and the finding of suitable employment. It is suggested that the rehabilitation problems and needs of all dwarfs are similar, irrespective of the etiology of the dwarfism.

Activities of Daily Living↗

[A fatal syndrome associating a micromelic dwarfism, an ichthyosiform skin disorder and a severe combined immunologic deficiency. Report of a case and survey of the literature (author's transl)].

Congenital immunologic deficiencies and congenital dwarfisms represent two seemingly unrelated disorders. Here is reported the tenth case of a definite congenital and fatal syndrome associating a severe combined immunologic deficiency and a micromelic dwarfism, affecting mainly the proximal limbs, as well as an ichtyosiform and furrowed skin disorder. Although the adenosine deaminase activity has not been determined in this patient, a 4-month old boy, this syndrome seems to be different from cases of ADA negative SCID. The associated impairment of growth and immunity emphasizes once more the close genetic linkage existing between the development of the skeleton and the lymphoid tissue.

Adenosine Deaminase↗

[Psychosocial dwarfism].

A 4 year old girl with psychosocial dwarfism showed hepatomegaly, abdominal distension and behavioral disturbances. Laboratory tests revealed a reversible elevation of serum liver enzymes and a reversible partial growth hormone deficiency. The child's family was characterised by severe social problems and all signs of a depriving and child abusing environment. All pathologic findings were reversed by removing the child from her depriving family background. This case demonstrates that psychosocial dwarfism represents an aspect of child abuse (battered child syndrome).

Body Height↗