Thanatophoric dysplasia type 1 (TD1) is the most severe form of FGFR3-related skeletal dysplasia, with high perinatal mortality and no approved pharmacologic therapies. Vosoritide, a C-type natriuretic peptide analogue that counteracts FGFR3 overactivation, improves growth in achondroplasia, but its effects in TD1 remain unexplored. We report the response to vosoritide therapy in a 9-year-old girl with genetically confirmed TD1 (c.2420G>T). Vosoritide was initiated at a dose of 15 µg/kg/day subcutaneously and increased to 30 µg/kg/day after 16 months. Growth velocity, anthropometry, pulmonary function, densitometry, and safety were assessed longitudinally over 28 months. At baseline, height was 78.6 cm (-10.9 SDS) and annual growth velocity (AGV) 1.6 cm/year (-4.7 SDS). After 28 months, height increased by +1.3 SDS and AGV by +2.0 cm/year (+3 SDS from baseline). Lung vital capacity improved by 65%. Serial MRI demonstrated persistent severe foramen magnum stenosis without radiological progression. Adverse events were limited to transient injection-site reactions and mild vasovagal episodes; no major safety concerns emerged. Vosoritide was well tolerated and improved growth velocity and lung function in this long-term TD1 survivor, suggesting therapeutic potential even in severe FGFR3 overactivation. Given TD1's rarity, larger studies and further off-label experience are essential to validate these findings.

The current case report presents the postmortem examination findings of a 17-week-old female fetus displaying thanatophoric dysplasia type 1 (TD-1) due to a known fibroblast growth factor receptor 3 (FGFR3) gene mutation. Gross and X-ray examination revealed significant abnormalities, including skeletal malformations with prominent TD-1 femur curvature. Microscopical evaluation indicated inadequate histological growth for the gestational age, with specific organ immaturity noted in multiple hematoxylin and eosin sections from internal organs, bone from epiphyses and diaphyses levels. Immunohistochemical analysis was conducted using specific markers, such as S100, CD34, CD117, glycophorin-C, and myeloperoxidase, to identify various hematopoietic and mesenchymal cell types. Furthermore, this report underscores the often-overlooked aspect of fetal hematopoiesis in cases diagnosed with TD-1, shedding light on the development of hematopoietic cells and their markers in various tissues, with a particular emphasis on the investigation of bone marrow foci in areas with incipient or no apparent ossification. Immunohistochemical identification of hematopoiesis also served as an indirect way to identify areas of incipient or abnormal ossification.

ObjectiveThe aim of this study was to classify the fetal skeletal dysplasias (FSD) in a series of affected fetuses based on radio-pathologic criteria. Materials and methods: We gathered clinicopathologic data of 72 cases which were diagnosed among 5995 autopsies performed over a 8-year period. Results: The prevalence of FSD was 1.2:100 autopsies. The overall sex ratio (M:F) was 1.25. Gestational age was between 17 and 24 weeks in 60% of cases. The FSD were classified into 13 distinct pathologic groups. Four major groups were identified: (1) Osteogenesis imperfecta (21 cases, 29%); (2) FGFR3 chondrodysplasia (18 cases, 25%); (3) Ciliopathies (9 cases, 12%); and (4) Sulfation disorders (7 cases, 10%). Thanatophoric dysplasia type 1 and lethal osteogenesis imperfecta were the most common skeletal dysplasias. Conclusion: Our study demonstrates the usefulness of the radio-pathologic examination in the diagnosis and accurate classification of the FSD, thus enabling better targeting of genetic counseling.

Thanatophoric dysplasia type 1 (TD1) is a lethal form of osteochondral dysplasia due to mutation of FGFR3 gene. In addition to severe shortening of the limbs there is temporo-occipital lobe dysplasia along with a range of other CNS anomalies. In this report we describe the radiological and anatomical features at autopsy in neonate with TD1 along with the CNS anomalies. We have also summarized the key distinguishing features of TD1 from other common types of osteochondral dysplasia. An accurate diagnosis is important for genetic counseling and impact on future pregnancies.

Obstetric ultrasonography is routinely used to screen for fetal anomalies. Thanatophoric dysplasia (TD) is one of the common though rare lethal skeletal dysplasia, detected during routine ultrasound scan. TD is caused by a mutation in FGFR3 gene. Characteristic features include shortening of limbs, macrocephaly and platyspondyly. In our local setting, it is common to miss the diagnosis in the early scans due to lack of expertise of the sonographers. To the best of our knowledge, this is the first publication from Ghana. Case Presentation. We present the case of a 33-year-old woman who was referred to the facility on account of ultrasound scan report suggestive of thanatophoric dysplasia type 1 at 34 weeks of a female baby. The diagnosis was not made despite the mother being a regular antenatal attendant, until a fifth scan done at 34 weeks reported features suggestive of thanatophoric dysplasia. The ultrasound scan features included a biparietal diameter of 37weeks, femur length-24weeks, narrowed thoracic cage with hypoplastic lungs and short ribs. The liquor volume was increased with amniotic fluid index (AFI) of 38.4 cm. The femur, tibia, fibula, humerus, ulna, and radius were shortened (micromelia). The diagnosis of thanatophoric dysplasia type 1 was confirmed on autopsy. This report was aimed to highlight the potential contribution of ultrasound scan in the diagnosis of thanatophoric dysplasia in our setting.