Prenatal Ultrasonographic Diagnosis of Rhizomelic Chondrodysplasia punctata by Detection of Rhizomelic Shortening and Bilateral Cataracts

Antenatal ultrasonographic diagnosis of rhizomelic chondrodysplasia punctata

BACKGROUND

Rhizomelic chondrodysplasia punctata (RCDP) is a rare autosomal recessive inherited subtype of a family of congenital anomalies known as chondrodysplasia calcificans punctate (CCP). Given their low rate of occurrence, these cases are highly challenging to diagnose, and because the presence of chondrodysplasia is an indication for legal abortion in Iran, such diagnosis is extremely critical.

CASE PRESENTATION

A 27-year-old white multipara was referred for obstetric ultrasonography at 17 weeks and 6 days of gestation because an ultrasonographic study performed at an outside institution revealed a short femur length. Given the patient's positive family history of chondrodysplasia, she underwent targeted sonography to check the anomaly of the bone and cartilage. The key finding in the sonography was short bones for gestational age.

CONCLUSION

The important clue in this finding was the patient's family history, which made the gynaecologist request an ultrasound to prevent the birth of a child with a congenital disorder. Genetic tests are usually performed on amniocentesis samples. Because the presence of chondrodysplasia is an indication for legal abortion in Iran, finally, the patient underwent legal abortion after amniocentesis and genetic tests.

A new GNPAT variant of foetal rhizomelic chondrodysplasia punctata

Background

Rhizomelic chondrodysplasia punctata (RCDP) is a clinical entity resulting from defects of peroxisomal metabolism whose clinical phenotype is characterized by rhizomelia, calcified foci in periarticular cartilage, coronal lesions of vertebral bodies, cataracts and severe cognitive delay. Usually, survival does not exceed the first decade of life. Transmission is autosomal recessive and is related to mutations in the PEX7, GNPAT or AGPS.

Methods

A detailed description of the prenatal ultrasound signs of RCDP found in two successive pregnancies in a consanguineous couple is reported. Molecular genetic investigations included the study of the coding regions and the exon–intron junctions of the GNPAT (high‐throughput amplification and sequencing performed with Roche NimbleGen SeqCap Target kit on Illumina platform); the confirmation test was carried out by amplification and Sanger sequencing with automatic capillary sequencer.

Results

In addition to the typical prenatal ultrasound signs described in the literature in association with RCDP, the presence of prefrontal oedema, never previously described, has been detected in both pregnancies. Moreover, genetic investigations have found a new splicing variant c.924+1G>A of the homozygous GNPAT.

Conclusion

The role of mutation in the GNPAT suggests a likely association with the clinical phenotype.

Neonatal Rhizomelic Chondrodysplasia Punctata Type 1: Weaving Evidence Into Clinical Practice

Rhizomelic chondrodysplasia punctata (RCDP) is a rare genetic peroxisome biogenesis disorder with a reported incidence of 1 in 100 000 live births. The 3 genetic subtypes of RCDP are acquired by an autosomal recessive inheritance pattern. RCDP type 1 accounts for greater than 90% of all aggregate cases. Differentiating between the 3 subtypes of RCDP, as well as disorders characterized by similar punctate cartilaginous changes, is essential to guide an appropriate postnatal plan of care. Management strategies are focused toward associated clinical manifestations and require an interdisciplinary approach including ophthalmology, cardiovascular, endocrine, physical and occupational therapy, and neurology. Purposeful and frequent collaboration among all members of the neonatal/pediatric interdisciplinary team is necessary to optimize outcomes for the neonate and the family unit. The purpose of this article is to anticipate the needs of both patients with known and prenatal diagnosis of RCDP type 1 and patients with suspected clinical diagnosis of RCDP type 1 in the immediate neonatal period and to guide the appropriate plan of care. This article presents a case report of type I RCDP, as well as describes genetic influences, symptoms, diagnosis, management, and prognosis.

The importance of ether-phospholipids: a view from the perspective of mouse models

Ether-phospholipids represent an important group of phospholipids characterized by an alkyl or an alkenyl bond at the sn-1 position of the glycerol backbone. Plasmalogens are the most abundant form of alkenyl-glycerophospholipids, and their synthesis requires functional peroxisomes. Defects in the biosynthesis of plasmalogens are the biochemical hallmark of the human peroxisomal disorder Rhizomelic Chondrodysplasia Punctata (RCDP), which is characterized by defects in eye, bone and nervous tissue. The generation and characterization of mouse models with defects in plasmalogen levels have significantly advanced our understanding of the role and importance of plasmalogens as well as pathogenetic mechanisms underlying RCDP. A review of the current mouse models and the description of the combined knowledge gathered from the histopathological and biochemical studies is presented and discussed. Further characterization of the role and functions of plasmalogens will contribute to the elucidation of disease pathogenesis in peroxisomal and non-peroxisomal disorders. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of Peroxisomes in Health and Disease.

Rhizomelic chondrodysplasia punctata type 1: report of mutations in 3 children from India

Rhizomelic chondrodysplasia punctata is a rare autosomal recessive disorder characterized by stippled epiphyses and rhizomelic shortening of the long bones. We report 3 subjects of rhizomelic chondrodysplasia punctata from India and the PEX7 mutations identified in them. The common PEX7-L292X allele, whose high frequency is due to a founder effect in the northern European Caucasian population, was not identified in these patients. Instead, 2 novel alleles are described, including 64_65delGC, which was present on a single PEX7 haplotype and could represent a common allele in the Indian population.

MRI of the fetal eyes: morphologic and biometric assessment for abnormal development with ultrasonographic and clinicopathologic correlation

BACKGROUND

Currently ocular biometric measurements are defined by US and are measured from the orbital walls. These bony landmarks cannot be seen by MRI, and therefore these measurements cannot be directly applied.

OBJECTIVE

To define measurements of normal growth of the fetal eyes using MRI.

MATERIALS AND METHODS

Transorbital views were analyzed in 198 fetal MR examinations. The ocular diameter (OD) and interocular and binocular distances (IOD and BOD) were measured and were plotted against gestational age. Fetuses with abnormalities affecting the eyes were evaluated separately.

RESULTS

Of 198 scans, 146 had suitable images, 35 of which were abnormal. Normal growth of BOD, IOD and OD were determined, and compared with the respective already established US data.

CONCLUSION

Normal growth charts were derived from a cohort of 111 normal fetuses. Because the margins of the vitreous are inside the bony orbit, at the same gestational age measurements of the BOD and OD are always less than the corresponding measurements by US, and those of the IOD are always more. Normal growth charts for MRI can now be used to support suspected diagnoses of orbital and ocular pathologies and the syndromes that give rise to them, and many examples are demonstrated.

PRENATAL DIAGNOSIS OF SKELETAL DYSPLASIAS

Skeletal anomalies occur with a frequency of around 1:500 and can present a diagnostic challenge when detected prenatally. Increasingly more sophisticated imaging such as MRI or CT may elucidate features more easily interpreted by postnatal radiologists. The aetiology of these anomalies is varied and includes aneuploidy, genetic syndromes, skeletal dysplasias, teratogens, disruption and maternal disease, making a multidisciplinary approach to the diagnosis essential. The estimated prevalence of skeletal dysplasias varies from 2–3/10,000 to 4–7/10,000 and diagnosis may require biochemical, cytogenetic, molecular genetic or haematological investigation. Clinical genetic input is often required as the family history or parental examination may yield valuable clues to the diagnosis. This review will briefly describe the normal embryology and sonographic appearances of fetal limb development and go on to suggest a systematic approach to the diagnosis of fetal skeletal dysplasias.