isolated growth hormone deficiency type IB

Isolated Growth Hormone Deficiency Type IB (IGH1B)

Isolated growth hormone deficiency type IB, also known as IGHD type IB, is a rare genetic disorder characterized by low but detectable levels of growth hormone (GH) in the body. This condition is inherited in an autosomal recessive manner, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the disorder.

Key Features:

• Low but detectable levels of GH
• Short stature, typically more than 2 standard deviations (SD) below the mean for age and sex
• Autosomal recessive inheritance pattern

People with IGHD type IB produce very low levels of growth hormone, which leads to short stature. This condition is distinct from other forms of growth hormone deficiency, where GH levels are undetectable.

References:

• [1] People with isolated growth hormone deficiency type IB produce very low levels of growth hormone. As a result, type IB is characterized by short stature. (Source: #4)
• Isolated growth hormone deficiency type IB (IGH1B) is an autosomal recessive disorder characterized by low but detectable levels of GH, short stature (more than 2 SD below the mean for age and sex). (Sources: #3, #7, #9)
• IGHD type IB is an autosomal recessive disorder characterized by low but detectable levels of GH, short stature (more than 2 SD below the mean for age and sex), ... (Source: #9)

Signs and Symptoms of Isolated Growth Hormone Deficiency Type IB

Isolated growth hormone deficiency (IGHD) type IB is a rare congenital disorder characterized by growth hormone deficiency and postnatal growth failure. The main signs and symptoms of IGHD type IB include:

• Short stature: Patients with IGHD type IB are typically short for their age, with a height that is less than 2 standard deviations (SDS) below the mean for their sex.
• Growth failure: Growth failure in IGHD type IB is not as severe as in type IA, but it can still be significant. Children may grow less than about 1.4 inches in height per year after their third birthday.
• Reduced energy levels: Patients with IGHD type IB may experience reduced energy levels and fatigue.
• Altered body composition: Altered body composition, including increased fat mass and decreased muscle mass, can also be a feature of IGHD type IB.
• Osteoporosis: Osteoporosis (reduced bone mineral density) is another potential complication of IGHD type IB.

Additional symptoms

In some cases, patients with IGHD type IB may experience additional symptoms, including:

• Jaundice: Jaundice, hypoglycemia, and/or underdeveloped male genitalia may be signs of neonatal GHD.
• Microcephaly: Microcephaly (small head size) can also be a feature of IGHD type IB.

Diagnosis

The diagnosis of IGHD type IB is typically made through a combination of clinical history, examination with detailed auxology, biochemical testing, and genetic analysis. Biochemical tests may include measurements of growth hormone levels, insulin-like growth factor 1 (IGF-1) levels, and other hormone levels.

References:

• [6] Isolated growth hormone deficiency (IGHD) is a rare congenital disorder characterized by growth hormone deficiency and postnatal growth failure.
• [5] Patients with IGHD type IB are characterized by low but detectable levels of GH (<7 mU/l; <2.5 ng/ml), short stature (<−2 SDS for age and sex), growth ...
• [4] It is characterized by a number of variable symptoms

Based on the provided context, here are the diagnostic tests for isolated growth hormone deficiency type IB:

• Insulin tolerance test: This is one of the most common tests for diagnosing growth hormone deficiency in adults (Source: [4]). The insulin tolerance test involves administering insulin to lower blood sugar levels and measuring the body's response.
• Genetic testing: Genetic testing can be used to confirm a diagnosis of isolated growth hormone deficiency type IB, which is an autosomal recessive disorder (Sources: [2], [3]).
• Biochemical testing: Biochemical testing, including measurement of GH levels, can also be used to diagnose growth hormone deficiency in childhood and adults (Source: [9]).

It's worth noting that a diagnosis of isolated growth hormone deficiency type IB typically involves a combination of clinical history, examination, and biochemical testing. A healthcare professional may use these tests in conjunction with other diagnostic tools to confirm a diagnosis.

References: [2] Genetic Testing Registry: Isolated growth hormone deficiency type IB [3] Clinical resource with information about Isolated growth hormone deficiency type IB and its clinical features, GH1, available genetic tests from US and labs [4] One of the most common tests for diagnosing growth hormone deficiency in adults is the insulin tolerance test. [9] by KS Alatzoglou · 2014 · Cited by 165 — The diagnosis of GH deficiency (GHD) in childhood is a multistep process involving clinical history, examination with detailed auxology, biochemical testing, ...

Treatment Options for Isolated Growth Hormone Deficiency Type IB

People with isolated growth hormone deficiency type IB (IGHD IB) can be effectively treated with synthetic growth hormone injections. This treatment approach is aimed at replacing the deficient growth hormone and promoting normal growth and development.

• Subcutaneous Synthetic GH Injections: The mainstay treatment for IGHD IB involves subcutaneous injections of synthetic growth hormone, administered until mid-parental height is reached [5]. This treatment has been shown to be effective in increasing short-term height velocity and promoting catch-up growth [9].
• Recombinant Human Growth Hormone (rhGH): Children with IGHD IB receive replacement therapy with daily injections of recombinant human GH (rhGH) [9]. RhGH therapy is effective in increasing short-term height velocity and promoting normal growth and development.
• Good Response to Treatment: Individuals with IGHD IB typically show a good response to rhGH treatment without antibody formation, which is an important consideration for long-term treatment efficacy [11].

Key Considerations

When it comes to treating IGHD IB, it's essential to consider the following factors:

• Type of Treatment: Synthetic growth hormone injections are the primary treatment approach for IGHD IB.
• Treatment Duration: Treatment typically continues until mid-parental height is reached.
• Response to Treatment: Individuals with IGHD IB generally show a good response to rhGH treatment without antibody formation.

References

[5] Amar, J. Y. (2017). Mainstay treatment is subcutaneous synthetic GH injection until mid-parental height is reached. [Cited by 2]

[9] Ibba, A. (2024). Children with GHD receive replacement therapy with daily injections of recombinant human GH (rhGH). RhGH therapy is effective in increasing short-term height velocity and promoting normal growth and development.

[11] Alatzoglou, A., et al. (2014). IGHD type IB is an autosomal recessive disorder characterized by low but detectable levels of GH, short stature, delayed bone age, and a good response to rhGH treatment without antibody formation.

Isolated Growth Hormone Deficiency Type IB (IGHD IB): Differential Diagnosis

Isolated growth hormone deficiency type IB (IGHD IB) is a rare genetic disorder characterized by low but detectable levels of growth hormone, short stature, and delayed bone age. The differential diagnosis for IGHD IB involves ruling out other conditions that may present with similar symptoms.

Conditions to Consider:

• Idiopathic Short Stature: This condition is often considered in children with short stature without any apparent cause. However, IGHD IB can be distinguished by the presence of low but detectable levels of growth hormone and delayed bone age [12].
• Primary Hypopituitarism: This condition involves a deficiency of one or more pituitary hormones, including growth hormone. IGHD IB is a specific type of primary hypopituitarism that affects only the production of growth hormone [15].
• Other forms of Growth Hormone Deficiency: IGHD IB should be differentiated from other forms of growth hormone deficiency, such as isolated growth hormone deficiency type IA (IGHD IA), which presents with more severe short stature and no detectable levels of growth hormone [2].

Diagnostic Criteria:

The diagnosis of IGHD IB is based on the following criteria:

• Low but detectable levels of growth hormone
• Short stature (more than 2 SD below the mean for age and sex)
• Delayed bone age
• Autosomal recessive inheritance pattern

Genetic Testing:

Genetic testing can be used to confirm the diagnosis of IGHD IB