Congenital autosomal recessive small-platelet thrombocytopenia, also known as CARST, is a rare condition that presents in the neonatal period with a reduced platelet count and an increased tendency to bleed. Affected individuals manifest with a range of bleeding symptoms, including a petechial rash, mucosal bleeding, and heavy menstrual bleeding where applicable. Despite the bleeding challenges, overall growth and development remain normal, and there is no heightened risk for infections. This condition is extremely uncommon, affecting fewer than one in a million people, and its precise genetic basis is still under investigation.

The clinical presentation is defined by an early onset of bleeding abnormalities. Newborns typically show signs such as a petechial rash and mucosal bleeding, which may raise concern soon after birth. As individuals grow, heavy menstrual bleeding can emerge in those who experience menses. Not all individuals experience every symptom, and severity varies considerably.

The precise genetic basis of congenital autosomal recessive small-platelet thrombocytopenia remains under investigation. Although the condition is described as autosomal recessive, a clear pattern of inheritance has not been definitively established from current data. It is thought that a combination of complex genetic and potential environmental factors contributes to the manifestation of the disorder. Genetic counseling can help families gain a better understanding of these uncertainties and the implications for family planning.