Deficiency in growth hormone that is either isolated
or combined with deficiency in other anterior pituitary hormones.
There are four types of pituitary
Pituitary Dwarfism type I: (Primordial Dwarfism; Sexual Ateleiotic Dwarfism; Isolated Autosomal
Recessive Growth Hormone Deficiency Dwarfism) is characterized by sexual
ateleiotic dwarfism, hypoglycemia, puppet (baby doll) facies, antibodies to
administered growth hormone. It is inherited as an autosomal recessive
Pituitary Dwarfism type II: (Laron Dwarfism type I; Laron Syndrome; Growth Hormone Receptor Deficiency
Syndrome; Growth Hormone Insensitivity Syndrome) is characterized by marked
short stature and short limbs. Clinical hyposomatotropism. However, the body
proportions in childhood appear normal. In the adult period, the body
proportions are childlike. Interestingly, the body proportions are more
marked in the stature than head size. There is increased resistance to the
action of growth hormone (GH). Occasionally blue sclerae. Other
clinical features include hip degeneration, limited elbow extensibility,
acrohypoplasia, and high-pitched voice. Distorted sex ratio (19F:2M) in Loja
province Ecuador cases. Markedly advanced osseous maturation for height and
age. It is believed to be cause by a failure to generate somatomedin (or
insulin-like growth factor, IGF1) in response to GH. Normal or increased
levels of GH. Growth hormone receptor (GHR) defect. Low IGF1 despite normal
or increased levels of GH. It is inherited as an autosomal recessive trait.
Pituitary Dwarfism type III: (Panhypopituitarism; Ateliotic Dwarfism with Hypogonadism Syndrome; Hanhart
Dwarfism; Rigid Cervical Spine Pituitary Hormone Deficiency Syndrome) is
characterized by ateliotic dwarfism, multiple endocrine anomalies
(hypothyroidism, hypoadrenalism, hypogonadism and panhypopituitarism),
neonatal hypoglycemia, and hypoglycemic seizures. Laboratory investigation
reveals the presence of sequential loss of anterior pituitary tropic
hormones, GH, gonadotropin, thyroid-stimulating hormone (TSH),
adrenocorticotropic hormone (ACTH), and prolactin deficiency. It is
inherited as an autosomal recessive trait.
Pituitary Dwarfism type IV: (Normal Immunoreactive Growth Hormone and Low Somatomedin Pituitary
Dwarfism Syndrome; Biodefective Growth Hormone Syndrome; Kowarski Syndrome)
is characterized by growth retardation, pituitary dwarfism, and delayed bone
age. Normal immunoreactive GH after stimulation, low somatomedin, exogenous
human GH responsive, structural abnormality of GH molecule confirmed the
diagnosis. It is inherited as an autosomal recessive trait.
The incidence of types I and II pituitary dwarfism are
not known, but panhypopituitary dwarfism is not excessively rare; there are
probably 7000 to 10,000 cases in the United States alone.
Both types I and II pituitary dwarfism are
inherited autosomal recessively. The human GHR gene is mapped to 5p13.1-p12.
Many cases of panhypopituitary dwarfism are caused by craniopharyngioma and
other nongenetic causes. The form inherited as an autosomal recessive or
X-linked form is rare.
There is a defect in the gene encoding GH
resulting in either biodefective GH, GH deficiency, or GHR deficiency. The
isolated GH deficiency in type I dwarfism may be the result of a defect in
hypothalamic releasing factor. Laron syndrome is caused by target resistance
to the action of GH.