isolated growth hormone deficiency type IA

Isolated growth hormone deficiency type IA is an inherited endocrine disorder caused by null mutations in the GH1 gene on chromosome 17q23.3. This condition, which follows an autosomal recessive inheritance pattern, leads to severe dwarfism with onset by six months of age. Affected infants present with marked growth delay and distinctive facial features such as a high forehead and depressed nasal ridge. While precise prevalence estimates are not available, this rare disorder may have variable development of antibodies to growth hormone following treatment. The severity and specific features can vary considerably from person to person.

The condition is characterized by a consistent set of features that include severe short stature, persistent open anterior fontanelle, and growth delay observed from infancy. Laboratory testing often reveals decreased serum insulin-like growth factor 1 and reduced circulating growth hormone concentrations. Other frequently observed clinical features include a high forehead, depressed nasal ridge, prolonged neonatal jaundice, and hypoglycemia. Not all individuals experience every feature, and severity varies considerably.

Isolated growth hormone deficiency type IA is caused by null mutations in the GH1 gene, which lead to an absence or marked reduction in functional growth hormone production. The condition is inherited in an autosomal recessive pattern, meaning that both copies of the gene in each cell must be altered for the condition to manifest. This mode of inheritance implies that each sibling of an affected individual has a 25% chance of being affected, and genetic counseling is recommended to help families understand these risks.

Currently, management focuses on supportive care and symptom management since there are no FDA-approved treatments specific to this condition. Treatment strategies are tailored to the individual and may include hormone supplementation to stimulate growth, although care must be taken due to the risk of developing antibodies following exogenous hormone administration. A multidisciplinary team approach, often including pediatric endocrinologists and growth specialists, is used to monitor and manage the condition. Genetic counseling is also recommended to provide guidance regarding family planning and long-term management options.

Outcomes in isolated growth hormone deficiency type IA vary depending on the severity of the hormone deficiency, age at diagnosis, and access to specialized care. With current standards of care, many individuals benefit from tailored supportive management, and treatment advances continue to improve the quality of life. That not all individuals experience all features and that severity can vary widely. Outcomes described in medical literature continue to evolve as standards of care improve, and families are encouraged to connect with endocrinologists and genetic counselors for personalized guidance.

Several clinical trials are currently investigating new treatment approaches for isolated growth hormone deficiency type IA. Individuals interested in clinical trials can search ClinicalTrials.gov or consult their care team about eligibility.