A 2022 review of anti-obesity treatments found that semaglutide as well as tirzepatide (which has an overlapping mechanism of action) were more promising than previous anti-obesity drugs, although less effective than bariatric surgery. Adverse effects
Side effects include nausea, vomiting, diarrhea, abdominal pain, and constipation. In people with heart problems, it can cause damage to the retina of the eye (retinopathy). Other, less common side effects include kidney problems, allergic reactions, low blood sugar, and pancreatitis. Contraindications
Due to data from rodents studies of GLP1 mediated thyroid C-cell hyperplasia, their use is contraindicated in patients with a personal or family history of medullary thyroid carcinoma and in patients with multiple endocrine neoplasia syndrome type 2. Mechanism of action
Semaglutide is a glucagon-like peptide-1 receptor agonist. By mimicking the action of the incretin GLP-1, it increases the production of insulin, a hormone that lowers the blood sugar level. It appears to enhance growth of pancreatic beta cells, which are responsible for insulin production and release. It also inhibits the production of glucagon, which is a hormone that increases glycogenolysis (release of stored carbohydrate from the liver) and gluconeogenesis (synthesis of new glucose). It reduces food intake by lowering appetite and slowing down digestion in the stomach, helping to reduce body fat. Its half-life in the blood is about seven days (165–184 hours). Structure
Semaglutide is chemically similar to human GLP-1, with 94% similarity. The only differences are two amino-acid substitutions at positions 8 and 34, where alanine and lysine are replaced by 2-aminoisobutyric acid and arginine, respectively.
Renpennings syndrome is a neurodevelopmental disorder recognised in males that causes intellectual disability, mild growth retardation with examples in the testes and head, and a somewhat short stature. The condition only affects males, starting at birth. Presentation
People with Renpennings typically begin learning language at an ordinary pace, but by the age of 3–4 they experience a regression in mental and physical development, such as mild low muscle tone resulting in elongated faces and rapid loss in the normal growth of the head (microcephaly). Small testes and short stature are also known to commonly occur. Genetics
It is associated with mutations in the PQBP1 gene. The gene product is a polyglutamine-binding protein involved in transcription and pre-mRNA splicing. The gene itself is located on the short arm of the X chromosome (Xp11.23). The most common mutations causing this condition occur in exon 4. Diagnosis
This diagnosis may be suspected on clinical grounds but should be confirmed by sequencing the PQBP1 gene. Treatment
There is no specific or curative treatment for this condition at present. Management is supportive

Epidemiology
This condition normally only occurs in males but a case in a female has been reported. History
This condition was first characterized in 1962. and later described by Hans Renpenning in 1963 after he documented these traits on many children in one family alone. See also
Lujan-Fryns syndrome
Fragile x syndrome

References


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