Radiological evaluation of dysmorphic thorax of paternal uniparental disomy 14

Adults with paternal UPD14 causing Kagami-Ogata syndrome: Case report and review of the literature

Kagami-Ogata syndrome (KOS) is a clinically recognizable syndrome in the neonatal period. It is characterized by specific skeletal anomalies and facial dysmorphisms. It is typically caused by paternal uniparental disomy of chromosome 14, while epimutations and microdeletions are less commonly reported causes. In the pediatric setting, KOS is a well delineated syndrome. However, there is a dearth of literature describing the natural history of the condition in adults. Herein, we describe a 35-year-old man, the first adult with KOS reported due to paternal uniparental disomy 14, and review reports of KOS in other affected adults. This highlights the variability in neurocognitive phenotypes, the presence of connective tissue abnormalities, and the uncertainties around long-term cancer risk.

Pediatric Ribs at Chest Radiography: Normal Variants and Abnormalities

Normal variants and abnormalities of the ribs are frequently encountered on chest radiographs. Accurate identification of normal variants is crucial to avoid unnecessary investigations. A meticulous evaluation of rib abnormalities can provide valuable insights into the patient's symptoms, and even when no osseous condition is suspected, rib abnormalities may offer critical clues to underlying conditions. Rib abnormalities are associated with various conditions, including benign tumors, malignant tumors, infectious and inflammatory conditions, vascular abnormalities, metabolic disorders, nonaccidental injuries, malformation syndromes, and bone dysplasias. Abnormalities of the ribs are classified into three groups based on their radiographic patterns: focal, multifocal, and diffuse changes. Focal lesions are further subdivided into nonaggressive lesions, aggressive lesions, and infectious and inflammatory disorders. Radiologists should be aware of individual disorders of the pediatric ribs, including their imaging findings, relevant clinical information, and underlying pathogenesis. Differential diagnoses are addressed as appropriate. Since chest radiographs can suffice for diagnosis in certain cases, the authors emphasize a pattern recognition approach to radiographic interpretation. However, additional cross-sectional imaging may be necessary for focal lesions such as tumors or inflammatory conditions. Awareness of disease-specific imaging findings helps ascertain the nature of the lesion and directs appropriate management. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Quantitative assessment of coat-hanger ribs detected on three-dimensional ultrasound for prenatal diagnosis of Kagami-Ogata syndrome

Kagami-Ogata syndrome (KOS14) is a rare disease characterized by omphalocele, polyhydramnios and a bell-shaped thorax. Although the coat-hanger appearance of the ribs on postnatal X-rays is a key diagnostic finding of KOS14, its prenatal diagnosis remains challenging. We encountered a case of KOS14 diagnosed prenatally that showed omphalocele, polyhydramnios, and a bell-shaped narrow thorax. The coat-hanger angle (CHA) measured at the sixth thoracic vertebrae and the ribs using three-dimensional (3D) ultrasonography was 39°, reflecting the coat-hanger appearance of the ribs. Segmental uniparental disomy chromosome 14 (UPD(14)pat) was confirmed by a methylation analysis and microsatellite analysis after birth. The median CHA (minimum, maximum) in 25 normal fetuses was 19 (9, 26) degrees, and a sonographic CHA of 30° may be a border value for diagnosing KOS14. When the combination of omphalocele and polyhydramnios is found prenatally, 3D ultrasonography for CHA might aid in the differential diagnosis of KOS14.

Kagami-Ogata syndrome: a case report

BACKGROUND

Kagami-Ogata syndrome is a rare genetic imprinting disorder involving the 14q32.2 genomic location of chromosome 14. The estimated incidence is less than 1 per 1 million. Here we report a male neonate with Kagami-Ogata syndrome presenting with severe respiratory distress requiring mechanical ventilation since birth.

CASE PRESENTATION

A Sri Lankan male neonate born at term via caesarean section to a mother with type 1 diabetes mellitus and hypothyroidism developed respiratory distress immediately after birth. On examination, the baby had facial dysmorphism with a hirsute forehead, full cheeks, flat nasal bridge, elongated protruding philtrum, and micrognathia. His chest was small and bell shaped, and he had severe intercostal and subcostal recessions. His abdominal wall was lax and thin, with evidence of divarication of the recti. Bowel peristalsis was easily visible through the abdominal wall. The chest x-ray showed narrowing of the rib cage with crowding of the ribs in a "coat-hanger" appearance. The coat-hanger angle was 32°, and the mid-to-widest thoracic diameter was 68%. On the basis of facial dysmorphism, chest and anterior abdominal wall abnormalities, coat-hanger appearance of the rib cage, increased coat-hanger angle, and reduced mid-to-widest thoracic diameter, a clinical diagnosis of Kagami-Ogata syndrome was made. Owing to severe respiratory distress, the baby required intubation and ventilation immediately after birth. He was ventilator-dependent for 3 weeks; however, he was successfully weaned off the ventilator on day 22 after several failed extubation attempts. At 3-month follow-up, he had generalized hypotonia and mild global developmental delay. His developmental age corresponded to 2 months.

CONCLUSIONS

We report a patient with Kagami-Ogata syndrome presenting with respiratory distress immediately after birth. This case report highlights the importance of being aware of this rare condition, which could present as severe respiratory distress in term and preterm newborns. A positive diagnosis could avoid unnecessary treatment and aid in accurate prognostication.

Kagami-Ogata Syndrome: Case Series and Review of Literature

Kagami-Ogata syndrome (KOS) (OMIM #608149) is a genetic imprinting disorder affecting chromosome 14 that results in a characteristic phenotype consisting of typical facial features, skeletal abnormalities including rib abnormalities described as "coat hanger ribs," respiratory distress, abdominal wall defects, polyhydramnios, and developmental delay. First identified by Wang et al in 1991, over 80 cases of KOS have been reported in the literature. KOS, however, continues to remain a rare and potentially underdiagnosed disorder. In this report, we describe two unrelated male infants with differing initial presentations who were both found to have the characteristic "coat hanger" rib appearance on chest X-ray, raising suspicion for KOS. Molecular testing confirmed KOS in each case. In addition to these new cases, we reviewed the existing cases reported in literature. Presence of polyhydramnios, small thorax, curved ribs, and abdominal wall defects must alert the perinatologist toward the possibility of KOS to facilitate appropriate molecular testing. The overall prognosis of KOS remains poor. Early diagnosis allows for counseling by a multidisciplinary team and enables parents to make informed decisions regarding both pregnancy management and postnatal care.

Skeletal ciliopathies: a pattern recognition approach

Ciliopathy encompasses a diverse group of autosomal recessive genetic disorders caused by mutations in genes coding for components of the primary cilia. Skeletal ciliopathy forms a subset of ciliopathies characterized by distinctive skeletal changes. Common skeletal ciliopathies include Jeune asphyxiating thoracic dysplasia, Ellis-van Creveld syndrome, Sensenbrenner syndrome, and short-rib polydactyly syndromes. These disorders share common clinical and radiological features. The clinical hallmarks comprise thoracic hypoplasia with respiratory failure, body disproportion with a normal trunk length and short limbs, and severely short digits occasionally accompanied by polydactyly. Reflecting the clinical features, the radiological hallmarks consist of a narrow thorax caused by extremely short ribs, normal or only mildly affected spine, shortening of the tubular bones, and severe brachydactyly with or without polydactyly. Other radiological clues include trident ilia/pelvis and cone-shaped epiphysis. Skeletal ciliopathies are commonly associated with extraskeletal anomalies, such as progressive renal degeneration, liver disease, retinopathy, cardiac anomalies, and cerebellar abnormalities. In this article, we discuss the radiological pattern recognition approach to skeletal ciliopathies. We also describe the clinical and genetic features of skeletal ciliopathies that the radiologists should know for them to play an appropriate role in multidisciplinary care and scientific advancement of these complicated disorders.

Kagami-Ogata syndrome in a fetus presenting with polyhydramnios, malformations, and preterm delivery: a case report

Background

Kagami–Ogata syndrome is also known as paternal uniparental disomy 14 and related disorders and is caused by abnormal genomic imprinting in the long arm of the chromosome 14q32.2 region. Its clinical manifestations include polyhydramnios in the fetal stage, respiratory insufficiency because of a small thorax, abdominal wall abnormalities, and peculiar facial features after birth.

Case presentation

A 38-year-old Japanese primigravida woman was referred to our hospital in the 19th week of pregnancy for suspected omphalocele. She had a history of hypothyroidism but was prescribed orally administered levothyroxine (50 μg/day) prior to conception and was euthyroid. Her ultrasound scan prior to visiting our hospital revealed fetal omphalocele, heavy for date, and polyhydramnios. The mother was advised to be admitted for observation from 28 weeks of gestation for threatened premature delivery. She required amniodrainage at 29 and 32 weeks of gestation. At 35 weeks of gestation, the fetal membrane prematurely ruptured and she gave birth after an emergency Cesarean section. The infant was a male child with a birth weight of 3188 g, and was suspected to have Kagami–Ogata syndrome after birth based on thoracic hypoplasia, swallowing function abnormalities, and peculiar facial features. A definitive diagnosis was established by performing genetic testing of the infant after obtaining informed written consent from both the parents; the results of the genetic testing revealed hypermethylated intergenic-differentially methylated region and maternally expressed gene 3-differentially methylated region in the corresponding chromosome 14 region. Both the parents were genetically tested after adequate genetic counseling, which revealed a de novo microdeletion in a differentially methylated region.

Conclusion

Kagami–Ogata syndrome should have been suspected because of the presence of polyhydramnios and omphalocele during pregnancy. Respiratory insufficiency soon after birth, because of a small thorax, is expected in this disease and a diagnosis during pregnancy may have enabled appropriate care after birth.

Anesthetic management of a child with Kagami-Ogata syndrome complicated with marked tracheal deviation: a case report

Background

Kagami-Ogata syndrome (KOS) is a rare congenital imprinting disorder. The problems related to the anesthetic management of patients with KOS are respiratory distress and difficult endotracheal intubation.

Case presentation

A 2-year-old male was scheduled to undergo orchiopexy for bilateral cryptorchidism. Although he had a history of severe respiratory distress immediately after birth, his preoperative respiratory condition was stable. He also had marked tracheal deviation. General anesthesia was induced with nitrous oxide and sevoflurane in oxygen. A laryngeal mask airway (LMA) was inserted following rocuronium administration. Anesthesia was maintained with sevoflurane and simultaneous caudal anesthesia. His postoperative course was uneventful.

Conclusions

Patients with KOS should preferably undergo elective surgery only after infancy because their respiratory status is more stable as they grow older. Thorough preoperative evaluation of the respiratory tract is important even in KOS patients with a stable respiratory condition.

The first de novo non-mosaic 14q11.2q13.1 tetrasomy of paternal origin

Tetrasomy 14q11q13 is a very rare chromosome aberration. So far, only five patients with such an imbalance were described. All these patients had a de novo marker chromosome idic(14)(q13) leading to a partial tetrasomy of chromosome 14. We report on the first case of a de novo non-mosaic partial tetrasomy 14q resulted not from a marker chromosome, but from an inverted triplication on paternal chromosome 14, characterized by using FISH and SNP array. Our patient showed some anomalies described in tetrasomy 14q11q13 with striking presence of paternal UPD(14) features (blepharophimosis, small thorax, and joint contractures, developmental delay). This unique patient supports the hypothesis that 14q11q13 may contain imprinted gene(s) that contribute to the paternal UPD(14) features of joint contractures and/or blepharophimosis. This patient demonstrates the utility of parent of origin testing in patients with de novo chromosome 14 aberrations. Overdosage of 14q11.1q13.1 may cause some features related to UPD(14) phenotype.

Comprehensive clinical studies in 34 patients with molecularly defined UPD(14)pat and related conditions (Kagami-Ogata syndrome)

Paternal uniparental disomy 14 (UPD(14)pat) and epimutations and microdeletions affecting the maternally derived 14q32.2 imprinted region lead to a unique constellation of clinical features such as facial abnormalities, small bell-shaped thorax with a coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly, and polyhydramnios. In this study, we performed comprehensive clinical studies in patients with UPD(14)pat (n=23), epimutations (n=5), and microdeletions (n=6), and revealed several notable findings. First, a unique facial appearance with full cheeks and a protruding philtrum and distinctive chest roentgenograms with increased coat-hanger angles to the ribs constituted the pathognomonic features from infancy through childhood. Second, birth size was well preserved, with a median birth length of ±0 SD (range, -1.7 to +3.0 SD) and a median birth weight of +2.3 SD (range, +0.1 to +8.8 SD). Third, developmental delay and/or intellectual disability was invariably present, with a median developmental/intellectual quotient of 55 (range, 29-70). Fourth, hepatoblastoma was identified in three infantile patients (8.8%), and histological examination in two patients showed a poorly differentiated embryonal hepatoblastoma with focal macrotrabecular lesions and well-differentiated hepatoblastoma, respectively. These findings suggest the necessity of an adequate support for developmental delay and periodical screening for hepatoblastoma in the affected patients, and some phenotypic overlap between UPD(14)pat and related conditions and Beckwith-Wiedemann syndrome. On the basis of our previous and present studies that have made a significant contribution to the clarification of underlying (epi)genetic factors and the definition of clinical findings, we propose the name 'Kagami-Ogata syndrome' for UPD(14)pat and related conditions.