UNASSIGNED: Described for the first time in 1954, Jeune syndrome (JS), often called asphyxiating thoracic dystrophy, is a congenital musculoskeletal disease characterized by short ribs, a narrow thorax, and small limbs. In this study, we analyzed and presented our preliminary experience with a device for progressive internal distraction of the sternum (PIDS) in patients with symptomatic JS. In addition, we reviewed the contemporary English literature on existing surgical techniques for treating children with congenital JS.
UNASSIGNED: A retrospective analysis of pediatric patients (<18 years old) treated for symptomatic JS at our tertiary center between 2017 and 2023 was performed.
UNASSIGNED: We presented two patients with JS who underwent surgery using an internal sternal distractor, a Zurich II Micro Zurich Modular Distractor, placed at the corpus of the sternum among the divided halves.
UNASSIGNED: We obtained promising results regarding the safety and effectiveness of this less-invasive device for PIDS in patients with symptomatic JS. Further studies on long-term outcomes are needed to validate these findings.

Skeletal dysplasias (SDs) are a large, heterogeneous group of mostly genetic disorders that affect the bones and cartilage, resulting in abnormal growth and development of skeletal structures. The high clinical and genetic diversity in SDs cause difficulties in prenatal diagnosis. To establish a correct prognosis and better management, it is very important to distinguish SDs with poor life-limiting prognosis or lethal SDs from other ones. Bad prognosis in foetuses is assessed on the basis of the size of the thorax, lung volumes, long bones’ length, bones’ echogenicity, bones’ angulation or presented fractures, and the concomitant presence of non-immune hydrops or visceral abnormalities. To confirm SD diagnosis and perform family genetic consultation, rapid molecular diagnostics are needed; therefore, the NGS method using a panel of genes corresponding to SD or whole-exome sequencing (WES) is commonly used. We report a case of a foetus showing long bones’ shortening and a narrow chest with short ribs, diagnosed prenatally with asphyxiating thoracic dystrophy, also known as Jeune syndrome (ATD; OMIM 208500), caused by compound heterozygous variants in the DYNC2H1 gene, identified by prenatally performed rapid-WES analysis. The missense variants in the DYNC2H1 gene were inherited from the mother (c.7289T>C; p.Ile2430Thr) and from the father (c.12716T>G; p.Leu4239Arg). The DYNC2H1 gene is one of at least 17 ATD-associated genes. This disorder belongs to the ninth group of SD, ciliopathies with major skeletal involvement. An extremely narrow, bell-shaped chest, and abnormalities of the kidneys, liver, and retinas were observed in most cases of ATD. Next to lethal and severe forms, clinically mild forms have also been reported. A diagnosis of ATD is important to establish the prognosis and management for the patient, as well as the recurrence risk for the family.

Holoprosencephaly-polydactyly syndrome and asphyxiating thoracic dystrophy rarely overlap but if they do, they have poorer prognosis. Early prenatal detection of multiple congenital anomalies plays a crucial role in the management of pregnancy.

UNASSIGNED: Skeletal dysplasia is a condition associated with various abnormalities of the skeleton and comprises multiple groups of disorders. Antenatal ultrasonographic assessment of the skeletal dysplasia requires a robust and systematic assessment of the long bones, fetal thorax, skull, spine, pelvis, hands and the feet. Large number of diseases, their overlapping phenotypic features and the lack of systematic approach lead to diagnostic inefficiency. A precise molecular diagnosis also requires an elaborate antenatal sonographic assessment to reach a final diagnosis.
UNASSIGNED: A fetus with micromelia, thoracic dysplasia and polydactyly was detected on prenatal sonography. An algorithmic approach of this rare combination on prenatal sonography is highlighted.
UNASSIGNED: Fetal micromelia is a relatively common entity which can be subclassified into mild and severe types. The lethal nature of the condition requires assessment of the thoracic biometry which may further narrow down the diagnostic possibilities. The red flags or highlighting features of various conditions like polydactyly, hitch-hiker thumb deformity, ovoid tibia and absent fibula may lead to a specific diagnosis.
UNASSIGNED: A background knowledge of various types of micromelia, their lethal nature, associations and specific features of various differential skeletal dysplasia will always be useful, if employed in a systematic manner.

A narrow thorax with shortening of long bones is usually pointing to dysfunction of the primary cilia corresponding clinically to ciliopathies with major skeletal involvement. Mutations in at least 23 genes are likely to correspond to this clinical presentation: IFT43/52/80/81/122/140/172, WDR19/34/35/60, DYNC2H1, DYNC2LI1, CEP120, NEK1, TTC21B, TCTEX1D2, INTU, TCTN3, EVC 1/2 and KIAA0586. In addition to these, KIAA0753 variants were recently described in seven patients with Jeune asphyxiating thoracic dystrophy (ATD) (two first cousins, one unrelated patient and one fetus), Joubert syndrome (two siblings) and orofaciodigital syndrome type 6 (one patient). We present the clinical characteristics of a eighth such patient. This 4 year-old boy with narrow thorax, short limbs, severe respiratory and feeding difficulties from birth on had a history of hypotonia and developmental delay. On skeletal survey, short tubular bones (height - 5,5 SD) and a trident appearance of the pelvis were seen. Brain MRI showed cervical canal stenosis. Renal function was normal and moderate hepatomegaly was noted. A homozygous c.943C > T mutation in KIAA0753 was identified on whole exome sequencing, resulting in Gln315Ter premature termination of the corresponding protein. This case provides confirmation of an additional molecular basis for skeletal dysplasia and illustrates how ciliopathies due to mutations in a single gene may present as apparently distinct syndromes.

We previously reported exome sequencing in a short-rib thoracic dystrophy (SRTD) cohort, in whom recessive mutations were identified in SRTD-associated genes in 10 of 11 cases. A heterozygous stop mutation in the known SRTD gene WDR60 was identified in the remaining case; no novel candidate gene/s were suggested by homozygous/compound heterozygous analysis. This case was thus considered unsolved. Re-analysis following an analysis pipeline update identified a homozygous mutation in C21orf2 (c.218G > C; p.Arg73Pro). This homozygous variant was previously removed at the quality control stage by the default GATK parameter \"in-breeding co-efficient.\" C21orf2 was recently associated with both Jeune asphyxiating thoracic dystrophy (JATD) and axial spondylometaphyseal dysplasia (axial SMD); this particular mutation was reported in homozygous and compound heterozygous state in both conditions. Our case has phenotypic features of both JATD and axial SMD; and the extent of thoracic involvement appears more severe than in other C21orf2-positive cases. Identification of a homozygous C21orf2 mutation in this case emphasizes the value of exome sequencing for simultaneously screening known genes and identifying novel genes. Additionally, it highlights the importance of re-interrogating data both as novel gene associations are identified and as analysis pipelines are refined. Finally, the severity of thoracic restriction in this case adds to the phenotypic spectrum attributable to C21orf2 mutations.

Severe asphyxiating thoracic dystrophy (Jeune syndrome) is usually fatal. The authors used distraction osteogenesis in a severe case and achieved 45 mm distraction of the sternum and improvement in tidal volume, lung compliance, and mean airway pressure.

UNASSIGNED: We report the case of a premature, very low birth weight, newborn with stigmata of Jeune syndrome, a rare skeletal dysplasia, and marked renal involvement (i.e. remarkable prenatal oligohydramnios, histologic nephronophthisis-like pattern, macroscopic renal cysts, and renal failure), expanding the phenotype consistent with the continuum of syndromic ciliopathies.