Prenatal ultrasound and MRI Diagnosis of Jeune syndrome type I (asphyxiating thoracic dystrophy) with histology and post-mortem three-dimensional CT confirmation

Whole exome sequencing, clinical exome or targeted gene panels: what to choose for suspected lethal skeletal dysplasia (short rib thoracic dysplasia type IV)

Lethal skeletal dysplasias (SDs) are a heterogeneous group of rare but important genetic disorders characterised by abnormal growth and development of bone and cartilage. The phenotypic variation of SD highlights the complex aetiology for this group of disorders. Short rib polydactyly syndrome (SRPS) types I-IV are a group of rare congenital autosomal recessive types of SD.We report a case of a non-consanguineous couple whose two successive pregnancies were diagnosed with multiple congenital anomalies in fetuses suggestive of lethal SD (likely SRPS type IV) at 24 and 19 weeks period of gestation, respectively. Pregnancy was terminated, and the whole exome sequencing of the abortus for genetic analysis in the second pregnancy confirmed an autosomal recessive type of short rib thoracic dysplasia-4 (SRTD-4) also called SRPS in homozygous condition. Our case is unique as it was also associated with cystic hygroma which is a rare association with SRPS/SRTD-4.

A system-based approach to the genetic etiologies of non-immune hydrops fetalis

A wide spectrum of genetic causes may lead to nonimmune hydrops fetalis (NIHF), and a thorough phenotypic and genetic evaluation are essential to determine the underlying etiology, optimally manage these pregnancies, and inform discussions about anticipated prognosis. In this review, we outline the known genetic etiologies of NIHF by fetal organ system affected, and provide a systematic approach to the evaluation of NIHF. Some of the underlying genetic disorders are associated with characteristic phenotypic features that may be seen on prenatal ultrasound, such as hepatomegaly with lysosomal storage disorders, hyperechoic kidneys with congenital nephrosis, or pulmonary valve stenosis with RASopathies. However, this is not always the case, and the approach to evaluation must include prenatal ultrasound findings as well as genetic testing and many other factors. Genetic testing that has been utilized for NIHF ranges from standard chromosomal microarray or karyotype to gene panels and broad approaches such as whole exome sequencing. Family and obstetric history, as well as pathology examination, can yield additional clues that are helpful in establishing a diagnosis. A systematic approach to evaluation can guide a more targeted approach to genetic evaluation, diagnosis, and management of NIHF.

Fetal micromelia, thoracic dysplasia and polydactyly revisited: A case-based antenatal sonographic approach

Introduction

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.

Case report

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.

Discussion

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.

Conclusion

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.

Integrative mid-trimester anomaly (IMTA) chart: a novel sonographic approach for syndromatic challenges (pilot study)

OBJECTIVE

To validate the use of the integrative mid-trimester anomaly (IMTA) chart, a novel chart that aims to increase sonographers' ability to diagnose fetal syndromes and complex anomalies.

METHODS

This study was conducted between September 2014 and January 2015. Pregnant women who attended our hospital for fetal medicine consultation during the second trimester were recruited. The diagnosis was assigned by a qualified consultant. The research coordinator randomized women between two groups (each consisted of two sonographers with comparable experience) and each was then examined twice (once with and once without the chart). Supposed diagnosis, patient and sonographer satisfactions were reported.

RESULTS

Twenty five women were recruited. Their average age was 26.48 ± 4.49 years and gestational age at examination was 24.39 ± 6.39. There were 17 (68%) fetuses that had multiple anomalies. The duration of examination was comparable. However, patient and sonographer satisfactions were higher when the same women were examined with the chart (p < 0.0001). The accuracy of diagnosis was also significantly higher (p = 0.03).

CONCLUSION

The IMTA chart seems to be a useful tool for novice sonographers that could increase their diagnostic accuracy and improve their patient and their own satisfaction.