ASPP2 deficiency causes features of 1q41q42 microdeletion syndrome.

Chromosomal abnormalities are implicated in a substantial number of human developmental syndromes, but for many such disorders little is known about the causative genes. The recently described 1q41q42 microdeletion syndrome is characterized by characteristic dysmorphic features, intellectual disability and brain morphological abnormalities, but the precise genetic basis for these abnormalities remains unknown. Here, our detailed analysis of the genetic abnormalities of 1q41q42 microdeletion cases identified TP53BP2, which encodes apoptosis-stimulating protein of p53 2 (ASPP2), as a candidate gene for brain abnormalities. Consistent with this, Trp53bp2-deficient mice show dilation of lateral ventricles resembling the phenotype of 1q41q42 microdeletion patients. Trp53bp2 deficiency causes 100% neonatal lethality in the C57BL/6 background associated with a high incidence of neural tube defects and a range of developmental abnormalities such as congenital heart defects, coloboma, microphthalmia, urogenital and craniofacial abnormalities. Interestingly, abnormalities show a high degree of overlap with 1q41q42 microdeletion-associated abnormalities. These findings identify TP53BP2 as a strong candidate causative gene for central nervous system (CNS) defects in 1q41q42 microdeletion syndrome, and open new avenues for investigation of the mechanisms underlying CNS abnormalities.

Diagnostic utility of microarray testing in pregnancy loss.

OBJECTIVES: To determine the frequency of clinically significant chromosomal abnormalities identified by chromosomal microarray in pregnancy losses at any gestational age and to compare microarray performance with that of traditional cytogenetic analysis when testing pregnancy losses. METHODS: Among 535 fetal demise specimens of any gestational age, clinical microarray-based comparative genomic hybridization (aCGH) was performed successfully on 515, and a subset of 107 specimens underwent additional single nucleotide polymorphism (SNP) analysis. RESULTS: Overall, clinically significant abnormalities were identified in 12.8% (64/499) of specimens referred with normal or unknown karyotypes. Detection rates were significantly higher with earlier gestational age. In the subset with normal karyotype, clinically significant abnormalities were identified in 6.9% (20/288). This detection rate did not vary significantly with gestational age, suggesting that, unlike aneuploidy, the contribution of submicroscopic chromosomal abnormalities to fetal demise does not vary with gestational age. In the 107 specimens that underwent aCGH and SNP analysis, seven cases (6.5%) had abnormalities of potential clinical significance detected by the SNP component, including female triploidy. aCGH failed to yield fetal results in 8.3%, which is an improvement over traditional cytogenetic analysis of fetal demise specimens. CONCLUSIONS: Both the provision of results in cases in which karyotype fails and the detection of abnormalities in the presence of a normal karyotype demonstrate the increased diagnostic utility of microarray in pregnancy loss. Thus, chromosomal microarray testing is a preferable, robust method of analyzing cases of pregnancy loss to better delineate possible genetic etiologies, regardless of gestational age.

Neonatal presentation of lethal neuromuscular glycogen storage disease type IV.

A total of 11 types of glycogen storage disorders have been recognized with variable clinical presentations. Type IV, also known as Andersen disease, represents a rare subtype that can induce severe clinical findings early in life. We report on a patient with early fetal onset of symptoms with severe neuromuscular findings at birth. The pregnancy was further complicated by polyhydramnios and depressed fetal movement. At birth severe hypotonia was noticed requiring active resuscitation and then mechanical ventilation. His lack of expected course for hypoxic ischemic encephalopathy prompted genetic testing, including a muscle biopsy, which confirmed the diagnosis of glycogen storage disease IV (GSD IV). Mutation analysis of the glycogen branching enzyme 1 gene demonstrated a previously unrecognized mutation. We review recent information on early presentation of GSD IV with particular interest in the presentation of the neonatal lethal neuromuscular form of this rare disorder.

Heterogeneity in Wiedemann-Beckwith syndrome: anthropometric evidence.

Wiedemann-Beckwith syndrome (WBS) has attracted a great deal of attention because of its genetic complexity. Individuals with WBS can be identified objectively by anthropometric analysis. Craniofacial anthropometry in conjunction with multivariate statistical analysis can be used to define patterns of variability that appear to relate to specific modes of inheritance that have been proposed for WBS. Our data on 19 affected individuals and their first-degree relatives indicate that the pattern of inheritance rather than the age of subjects may be responsible for the highly variable craniofacial phenotype found in individuals diagnosed with WBS.

Late gestational vascular disruptions inducing craniofacial anomalies: a fetal lamb model.

We report our preliminary observations in six fetal lambs that were surgically manipulated in utero to impede the blood flow of the carotid arteries and their branches, including the laryngeal artery, the anastomotic branch between the vertebral artery and the occipital artery, the auricularis and the transverse facial arteries. Between 115 and 117 days of gestation (term pregnancy 147 days), all ewes were placed under general anesthesia and mechanical ventilation. Their fetuses were exteriorized and catheters were placed in their femoral artery for blood gas sampling. A balloon occluder and a blood flow probe were placed on one internal carotid while the contralateral side was completely ligated. On the third day post surgery, the balloon occluder was inflated three times for 30 minutes each time at 30 minute intervals in the experimental fetuses. PO2, PCO2, pH, lactate and glucose were monitored during the study. At 7 days post occlusion, all animals were sacrificed and tissues were collected. Craniofacial anomalies were obvious in three animals similar to those seen in hemifacial microsomia, Goldenhar syndrome and Pierre-Robin sequence. All three control animals had normal craniofacial structures. This preliminary data suggests that late gestation vascular disruptions may lead to significant craniofacial anomalies, as seen in our animal model.

Urorectal septum malformation sequence: report of thirteen additional cases and review of the literature.

We present the findings of 13 additional cases of the urorectal septum malformation (URSM) sequence, and review the literature. The URSM sequence consists of ambiguous genitalia concurrent with absence of perineal and anal openings. The sex ratio of the 13 new cases was 7 males to 6 females and from the literature 21 males and 28 females. In addition, 11 of the 13 new cases had anorectal atresia with 5 of the cases also having partial agenesis of the colon. Bilateral renal agenesis was present in 3 of the 13 cases, unilateral renal agenesis occurred in 6, and dysplastic kidneys were found in 10. The URSM sequence is a lethal condition with long-term survival reported in only 3 of a total of 62 literature and new cases. Recurrence of this condition has not been reported.

Quantitation of craniofacial anomalies in utero: fetal alcohol and Crouzon syndromes and thanatophoric dysplasia.

The study of fetal growth and development by ultrasound has been greatly facilitated in the past few years by the availability of anthropometric standards for the fetal body. Thus, the obstetrician is able to discern between normal and grossly abnormal, and even to quantitate certain fine fetal structures such as the face. This paper presents results obtained from a group of 5 patients referred to the Medical Center from private practices in Indianapolis, Indiana. Prenatal cephalometric analyses by ultrasound suggested the presence of craniofacial anomalies in all 5 cases. However, such defects were not detectable by routine ultrasonographic examination. A clinical examination after birth of each of these 5 patients suggested the following diagnoses: Fetal Alcohol Syndrome (FAS) in 2 individuals, Fetal Alcohol Effects (FAE) in one individual, Crouzon Syndrome (CS) in one patient, and Thanatophoric Dysplasia (TD) in one patient. In order to compare the craniofacial measurement values for each patient to normal standards, we developed Z-Score profiles and Pattern Variability Indexes (PVI) as described by Garn et al. [1984, 1985]. The values presented here support the idea that even mildly abnormal fetal craniofacial patterns are detectable by this relatively new application of ultrasound. At the present time, no conclusions can be made regarding the diagnostic accuracy of these patterns and profiles. However, the potential value of fetal cephalometry for documenting craniofacial dysmorphology is clearly indicated.

Bone dysplasias: the prenatal diagnostic challenge.

The prenatal diagnosis of bone dysplasias presents difficult challenges for the clinician involved in monitoring pregnancies. Such diagnoses highlight delicate ethical issues and may require difficult decision-making when the differential diagnosis includes a lethal bone dysplasia. Despite the rapid technological advances in ultrasonography, the ability to make prenatal diagnoses within this group of disorders is limited by the restricted ultrasonographic capability to appreciate fully the detailed fetal anatomy. However, we perceive that a significant further limitation involves the lack of a systematic protocol to guide the clinician in the ultrasonographic evaluation of a fetus suspected of having a skeletal dysplasia. In an attempt to aid the clinician who is evaluating these suspected pregnancies, we report here 8 cases and propose a model protocol for the ultrasonographic diagnostic approach to fetal skeletal problems in utero.

A morphometric analysis of the fetal craniofacies by ultrasound: fetal cephalometry.

We present here a set of 24 standardized linear measurements that describe the growth of different craniofacial structures in the normal fetus from 16 to 36 weeks of gestation. These measurements were taken from 89 pregnant women, who had from 1 to 3 ultrasonographic evaluations during the pregnancy (16, 26, and 36 weeks of gestation). All the values presented here were obtained using the technique described by Escobar et al. The mean and standard deviation was calculated for each measurement and was used to estimate the normal growth pattern of each variable. Approximate confidence intervals for the mean of each variable were constructed for use in identifying unusually low or high values. The confidence intervals are available in graphic form by request. These data will not only contribute to an understanding of fetal craniofacial growth and development in utero, but in addition, it will help to make the diagnoses of mild craniofacial anomalies that would not be detected by the routine ultrasonographic examination. We suggest that this procedure should be included if not in all routine obstetrical ultrasound evaluations, then at least in the more extensive level II obstetrical ultrasound.

Fetal craniofacial morphometrics: in utero evaluation at 16 weeks' gestation.

Although ultrasound has proved useful in the diagnosis of fetal craniofacial malformations, its success has been based primarily on subjective clinical observations of apparent abnormal fetal structures, their proportions, and unusual features. However, such clinical observations may be misleading and ideally should be validated by standardized quantitative measurements. We describe here an ultrasonographic methodology that has provided quantitative data describing the normal fetal craniofacies at 16 weeks of gestation. This report is part of an ongoing research project directed at describing fetal facial morphology in utero at different gestational ages. Such data can be used to construct growth curves to which observations from suspected abnormal fetuses can be compared. A total of 53 patients were evaluated at 16 weeks of gestation, at which time 24 craniofacial linear and angular measurements were made. The landmarks employed for these measurements were those used in roentgencephalometry so that this fetal data base could be related to postnatal populations. Such data will contribute not only to a description of facial dysmorphogenesis but also to a better understanding of normal facial growth and development. Furthermore, they constitute a useful tool for prenatal diagnosis, gestational aging, growth predictions, and perhaps for as yet relatively unexplored fields such as fetal therapy.

Antley-Bixler syndrome from a prognostic perspective: report of a case and review of the literature.

The Antley-Bixler syndrome (ABS) is characterized by craniosynostosis, radiohumeral synostosis, and femoral bowing. Other findings include a trapezoid-shaped head, deformed ears, severe midface hypoplasia, choanal atresia or stenosis, and long bone fractures. Most ABS cases have died in the first months of life from respiratory complications. The poor prognosis in this condition makes counseling difficult and early termination of pregnancy a consideration. The medical and surgical management information presented here can be used as a guide for counseling parents in the future. We report on a new patient with ABS who now at age 3 yr, has been followed by the medical staff of Riley Children's Hospital since birth. She has had successful medical and surgical management. Although the multisynostoses seen in this disorder is undoubtedly related to the soft tissue malformations such as choanal stenosis and midface hypoplasia, the cause remains unknown. The literature is also reviewed in this condition.

Urorectal septum malformation sequence. Report of six cases and embryological analysis.

We encountered six female infants with a specific pattern of developmental abnormalities of the urogenital and lower intestinal tracts. The anomalies included ambiguous genitalia, lack of perineal openings, and müllerian and urinary tract anomalies. Each patient had normal female chromosomes and normal adrenal gland function. We believe that this combination of anomalies represents a recognizable and specific sequence that is due to a failure of migration to and/or fusion of the urorectal septum with the cloacal membrane. This, in turn, we postulate, leads to persistence of the cloaca and cloacal membrane and failure of normal differentiation of the external genitalia. Persistence of the cloacal membrane results in absence of the urethral and vaginal openings and an imperforate anus. We propose calling this entity the urorectal septum malformation sequence.