Prenatal Diagnosis of Cartilage-Hair Hypoplasia: A Narrative Review

Cartilage-hair hypoplasia is a rare autosomal recessive skeletal dysplasia. It is particularly prevalent in the Finnish and Amish populations but increasing reports have been documented worldwide. It is caused by pathogenic variants in the RMRP gene. The clinical presentation is highly variable and may include short-limbed short stature, metaphyseal abnormalities, hypotrichosis, and immune deficiency, among other features. Some of the manifestations may present early in the prenatal period and ultrasound assessment is often the tool that raises suspicion for this condition. This review aims to summarize the current knowledge regarding the prenatal diagnosis of cartilage-hair hypoplasia, focusing on its molecular basis and the role of imaging and genetic testing. A comprehensive literature search was conducted in the PubMed/MEDLINE database using the terms 'Prenatal diagnosis', 'Cartilage-hair hypoplasia', 'Skeletal dysplasias', 'Osteochondrodysplasias' and 'RMRP mutation'. Prenatal diagnosis of this condition remains challenging, as ultrasound findings may overlap with other skeletal dysplasias, including lethal forms. Lethality predictors and the potential of molecular testing are also explored. A structured prenatal approach, combined with timely genetic counselling, may allow for an earlier diagnosis and support informed reproductive decisions. Given the recent advances in reproductive technologies and the potential impact of cartilage-hair hypoplasia on affected individuals, this condition should be actively considered in future studies addressing the prenatal diagnosis of skeletal dysplasias.