The impact of concurrent X chromosome anomalies on diagnosis and bleeding phenotype in children with hemophilia: A single-institution case series.

Hemophilia is an inherited X-linked bleeding disorder characterized by deficiencies of factors VIII or IX. Concomitant X chromosome disorders can impact bleeding phenotype, complicating timely diagnosis and disease management. Herein, we describe three cases of female and male pediatric patients with hemophilia A or B diagnosed between 6 days and 4 years old in the setting of skewed X chromosome inactivation, Turner syndrome, or Klinefelter syndrome. All of these cases had significant bleeding symptoms, and two patients required initiation of factor replacement therapy. One female patient developed a factor VIII inhibitor similar to that described in males with hemophilia A.

The emotional experience of mothers of children with haemophilia: maternal guilt, effective coping strategies and resilience within the haemophilia community.

INTRODUCTION: Mothers of children with haemophilia (CWH) experience guilt related to this genetic condition. Several factors contributing to maternal guilt have been identified, but the scope and extent of guilt have not previously been quantified. AIM: This study provides insight into the experience of mothers of CWH and how they perceive and manage guilt. It then identifies the most common and helpful coping mechanisms. METHODS: Between May and October 2021, we distributed an anonymous electronic survey to mothers of CWH. The Parent Experience of Child Illness measured maternal guilt, the PROMIS Parent Proxy for Life Satisfaction measured perception of their child's life satisfaction and additional questions explored specific guilt factors and coping strategies. RESULTS: Eighty-seven mothers responded to the survey. Forty percent of mothers experienced increased guilt. The most common reasons for guilt included putting their child through pain during infusions and passing on the affected X chromosome. Perceived life satisfaction, increased age and genetic counselling were associated with less guilt. The most common coping strategies involved utilizing social support, self-education and connecting with other mothers in the community. CONCLUSION: Some mothers experienced increased feelings of guilt, illustrating the need for providers to tactfully provide anticipatory guidance and counselling. Tangible manifestations of haemophilia were more likely to trigger feelings of guilt than familial factors. Community immersion was beneficial, as other mothers in the community served as a source of social and educational support. Most mothers did not report guilt, illustrating the adaptability and resilience of the haemophilia community.

Genome-Wide Association Study to Find Modifiers for Tetralogy of Fallot in the 22q11.2 Deletion Syndrome Identifies Variants in the GPR98 Locus on 5q14.3.

BACKGROUND: The 22q11.2 deletion syndrome (22q11.2DS; DiGeorge syndrome/velocardiofacial syndrome) occurs in 1 of 4000 live births, and 60% to 70% of affected individuals have congenital heart disease, ranging from mild to severe. In our cohort of 1472 subjects with 22q11.2DS, a total of 62% (n=906) have congenital heart disease and 36% (n=326) of these have tetralogy of Fallot (TOF), comprising the largest subset of severe congenital heart disease in the cohort. METHODS AND RESULTS: To identify common genetic variants associated with TOF in individuals with 22q11.2DS, we performed a genome-wide association study using Affymetrix 6.0 array and imputed genotype data. In our cohort, TOF was significantly associated with a genotyped single-nucleotide polymorphism (rs12519770, P=2.98×10-8) in an intron of the adhesion GPR98 (G-protein-coupled receptor V1) gene on chromosome 5q14.3. There was also suggestive evidence of association between TOF and several additional single-nucleotide polymorphisms in this region. Some genome-wide significant loci in introns or noncoding regions could affect regulation of genes nearby or at a distance. On the basis of this possibility, we examined existing Hi-C chromatin conformation data to identify genes that might be under shared transcriptional regulation within the region on 5q14.3. There are 6 genes in a topologically associated domain of chromatin with GPR98, including MEF2C (Myocyte-specific enhancer factor 2C). MEF2C is the only gene that is known to affect heart development in mammals and might be of interest with respect to 22q11.2DS. CONCLUSIONS: In conclusion, common variants may contribute to TOF in 22q11.2DS and may function in cardiac outflow tract development.

Examining the Overlap between Autism Spectrum Disorder and 22q11.2 Deletion Syndrome.

22q11.2 deletion syndrome (22q11.2DS) is a genomic disorder reported to associate with autism spectrum disorders (ASDs) in 15-50% of cases; however, others suggest that individuals with 22q11.2DS present psychiatric or behavioral features associated with ASDs, but do not meet full criteria for ASD diagnoses. Such wide variability in findings may arise in part due to methodological differences across studies. Our study sought to determine whether individuals with 22q11.2DS meet strict ASD diagnostic criteria using research-based guidelines from the Collaborative Programs of Excellence in Autism (CPEA), which required a gathering of information from three sources: the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observational Schedule (ADOS), and a clinician's best-estimate diagnosis. Our study examined a cohort of children, adolescents, and young adults (n = 56) with 22q11.2DS, who were ascertained irrespective of parents' behavioral or developmental concerns, and found that 17.9% (n = 10) of the participants met CPEA criteria for an ASD diagnosis, and that a majority showed some level of social-communication impairment or the presence of repetitive behaviors. We conclude that strictly defined ASDs occur in a substantial proportion of individuals with 22q11.2DS, and recommend that all individuals with 22q11.2DS be screened for ASDs during early childhood.

Rare copy number variants and congenital heart defects in the 22q11.2 deletion syndrome.

The 22q11.2 deletion syndrome (22q11DS; velocardiofacial/DiGeorge syndrome; VCFS/DGS; MIM #192430; 188400) is the most common microdeletion syndrome. The phenotypic presentation of 22q11DS is highly variable; approximately 60-75 % of 22q11DS patients have been reported to have a congenital heart defect (CHD), mostly of the conotruncal type, and/or aortic arch defect. The etiology of the cardiac phenotypic variability is not currently known for the majority of patients. We hypothesized that rare copy number variants (CNVs) outside the 22q11.2 deleted region may modify the risk of being born with a CHD in this sensitized population. Rare CNV analysis was performed using Affymetrix SNP Array 6.0 data from 946 22q11DS subjects with CHDs (n = 607) or with normal cardiac anatomy (n = 339). Although there was no significant difference in the overall burden of rare CNVs, an overabundance of CNVs affecting cardiac-related genes was detected in 22q11DS individuals with CHDs. When the rare CNVs were examined with regard to gene interactions, specific cardiac networks, such as Wnt signaling, appear to be overrepresented in 22q11DS CHD cases but not 22q11DS controls with a normal heart. Collectively, these data suggest that CNVs outside the 22q11.2 region may contain genes that modify risk for CHDs in some 22q11DS patients.

Compound heterozygous mutations in NEK8 in siblings with end-stage renal disease with hepatic and cardiac anomalies.

We studied two brothers who presented in the newborn period with cardiac, renal, and hepatic anomalies that were initially suggestive of ALGS, although no mutations in JAG1 or NOTCH2 were identified. Exome sequencing demonstrated compound heterozygous mutations in the NEK8 gene (Never in mitosis A-related Kinase 8), a ciliary kinase indispensable for cardiac and renal development based on murine studies. The mutations included a c.2069_2070insC variant (p.Ter693LeufsTer86), and a c.1043C>T variant (p.Thr348Met) in the highly conserved RCC1 (Regulation of Chromosome Condensation 1) domain. The RCC1 domain is crucial for localization of the NEK8 protein to the centrosomes and cilia. Mutations in NEK8 have been previously reported in three fetuses (from a single family) with renal-hepatic-pancreatic dysplasia 2 (RHPD2), similar to Ivemark syndrome, and in three individuals with nephronophthisis (NPHP9). This is the third report of disease-causing mutations in the NEK8 gene in humans and only the second describing multi-organ involvement. The clinical features we describe differ from those in the previously published report in that (1) a pancreatic phenotype was not observed in the individuals reported here, (2) there were more prominent cardiac findings, (consistent with observations in murine models), and (3) we observed bile duct hypoplasia rather than ductal plate malformation. The patients reported here expand our understanding of the NEK8-associated phenotype. Our findings highlight the variable phenotypic expressivity and the spectrum of clinical manifestations due to mutations in the NEK8 gene.

Histone Modifier Genes Alter Conotruncal Heart Phenotypes in 22q11.2 Deletion Syndrome.

We performed whole exome sequence (WES) to identify genetic modifiers on 184 individuals with 22q11.2 deletion syndrome (22q11DS), of whom 89 case subjects had severe congenital heart disease (CHD) and 95 control subjects had normal hearts. Three genes including JMJD1C (jumonji domain containing 1C), RREB1 (Ras responsive element binding protein 1), and SEC24C (SEC24 family member C) had rare (MAF < 0.001) predicted deleterious single-nucleotide variations (rdSNVs) in seven case subjects and no control subjects (p = 0.005; Fisher exact and permutation tests). Because JMJD1C and RREB1 are involved in chromatin modification, we investigated other histone modification genes. Eighteen case subjects (20%) had rdSNVs in four genes (JMJD1C, RREB1, MINA, KDM7A) all involved in demethylation of histones (H3K9, H3K27). Overall, rdSNVs were enriched in histone modifier genes that activate transcription (Fisher exact p = 0.0004, permutations, p = 0.0003, OR = 5.16); however, rdSNVs in control subjects were not enriched. This implicates histone modification genes as influencing risk for CHD in presence of the deletion.

Whole-Genome Sequencing and Integrative Genomic Analysis Approach on Two 22q11.2 Deletion Syndrome Family Trios for Genotype to Phenotype Correlations.

The 22q11.2 deletion syndrome (22q11DS) affects 1:4,000 live births and presents with highly variable phenotype expressivity. In this study, we developed an analytical approach utilizing whole-genome sequencing (WGS) and integrative analysis to discover genetic modifiers. Our pipeline combined available tools in order to prioritize rare, predicted deleterious, coding and noncoding single-nucleotide variants (SNVs), and insertion/deletions from WGS. We sequenced two unrelated probands with 22q11DS, with contrasting clinical findings, and their unaffected parents. Proband P1 had cognitive impairment, psychotic episodes, anxiety, and tetralogy of Fallot (TOF), whereas proband P2 had juvenile rheumatoid arthritis but no other major clinical findings. In P1, we identified common variants in COMT and PRODH on 22q11.2 as well as rare potentially deleterious DNA variants in other behavioral/neurocognitive genes. We also identified a de novo SNV in ADNP2 (NM_014913.3:c.2243G>C), encoding a neuroprotective protein that may be involved in behavioral disorders. In P2, we identified a novel nonsynonymous SNV in ZFPM2 (NM_012082.3:c.1576C>T), a known causative gene for TOF, which may act as a protective variant downstream of TBX1, haploinsufficiency of which is responsible for congenital heart disease in individuals with 22q11DS.

Copy-Number Variation of the Glucose Transporter Gene SLC2A3 and Congenital Heart Defects in the 22q11.2 Deletion Syndrome.

The 22q11.2 deletion syndrome (22q11DS; velocardiofacial/DiGeorge syndrome; VCFS/DGS) is the most common microdeletion syndrome and the phenotypic presentation is highly variable. Approximately 65% of individuals with 22q11DS have a congenital heart defect (CHD), mostly of the conotruncal type, and/or an aortic arch defect. The etiology of this phenotypic variability is not currently known. We hypothesized that copy-number variants (CNVs) outside the 22q11.2 deleted region might increase the risk of being born with a CHD in this sensitized population. Genotyping with Affymetrix SNP Array 6.0 was performed on two groups of subjects with 22q11DS separated by time of ascertainment and processing. CNV analysis was completed on a total of 949 subjects (cohort 1, n = 562; cohort 2, n = 387), 603 with CHDs (cohort 1, n = 363; cohort 2, n = 240) and 346 with normal cardiac anatomy (cohort 1, n = 199; cohort 2, n = 147). Our analysis revealed that a duplication of SLC2A3 was the most frequent CNV identified in the first cohort. It was present in 18 subjects with CHDs and 1 subject without (p = 3.12 × 10(-3), two-tailed Fisher's exact test). In the second cohort, the SLC2A3 duplication was also significantly enriched in subjects with CHDs (p = 3.30 × 10(-2), two-tailed Fisher's exact test). The SLC2A3 duplication was the most frequent CNV detected and the only significant finding in our combined analysis (p = 2.68 × 10(-4), two-tailed Fisher's exact test), indicating that the SLC2A3 duplication might serve as a genetic modifier of CHDs and/or aortic arch anomalies in individuals with 22q11DS.

The effect of hypocalcemia in early childhood on autism-related social and communication skills in patients with 22q11 deletion syndrome.

22q11 deletion syndrome (22qDS), also known as DiGeorge syndrome, is a copy number variant disorder that has a diverse clinical presentation including hypocalcaemia, learning disabilities, and psychiatric disorders. Many patients with 22q11DS present with signs that overlap with autism spectrum disorder (ASD) yet the possible physiological mechanisms that link 22q11DS with ASD are unknown. We hypothesized that early childhood hypocalcemia influences the neurobehavioral phenotype of 22q11DS. Drawing on a longitudinal cohort of 22q11DS patients, we abstracted albumin-adjusted serum calcium levels from 151 participants ranging in age from newborn to 19.5 years (mean 2.5 years). We then examined a subset of 20 infants and toddlers from this group for the association between the lowest calcium level on record and scores on the Communication and Symbolic Behavior Scales-Developmental Profile Infant-Toddler Checklist (CSBS-DP ITC). The mean (SD) age at calcium testing was 6.2 (8.5) months, whereas the mean (SD) age at the CSBS-DP ITC assessment was 14.7 (3.8) months. Lower calcium was associated with significantly greater impairment in the CSBS-DP ITC Social (p < 0.05), Speech (p < 0.01), and Symbolic domains (p < 0.05), in regression models adjusted for sex, age at blood draw, and age at the psychological assessment. Nevertheless, these findings are limited by the small sample size of children with combined data on calcium and CSBS-DP ITC, and hence will require replication in a larger cohort with longitudinal assessments. Considering the role of calcium regulation in neurodevelopment and neuroplasticity, low calcium during early brain development could be a risk factor for adverse neurobehavioral outcomes.

Severe aortopathy due to fibulin-4 deficiency: molecular insights, surgical strategy, and a review of the literature.

UNLABELLED: Mutations in the EFEMP2 (alias FBLN4) gene, which encodes the extracellular matrix protein fibulin-4, lead to severe aortopathy with aneurysm formation and vascular tortuosity. The disease phenotype, termed autosomal recessive cutis laxa type 1B (ARCL 1B), is rare among heritable connective tissue diseases but becomes more likely when noting family consanguinity and loose, inelastic skin in the patient. Our patient presented with an intercurrent illness exacerbating upper airway obstruction due to compression from a large aortic aneurysm. Genetic testing eventually revealed the causative mutation. She was initially treated with an angiotensin II receptor blocker and beta-blocker and eventually underwent total thoracic aortic replacement via a two-stage elephant trunk-type procedure. She recovered well and is currently asymptomatic but will require lifetime follow-up due to residual vascular tortuosity and aneurysm risk. CONCLUSION: Better understanding of the importance of transforming growth factor beta signaling in the pathophysiology of aortopathies such as ARCL 1B has led to targeted medical therapies. Specific surgical techniques can lead to optimal outcomes in these patients.

Enhanced maternal origin of the 22q11.2 deletion in velocardiofacial and DiGeorge syndromes.

Velocardiofacial and DiGeorge syndromes, also known as 22q11.2 deletion syndrome (22q11DS), are congenital-anomaly disorders caused by a de novo hemizygous 22q11.2 deletion mediated by meiotic nonallelic homologous recombination events between low-copy repeats, also known as segmental duplications. Although previous studies exist, each was of small size, and it remains to be determined whether there are parent-of-origin biases for the de novo 22q11.2 deletion. To address this question, we genotyped a total of 389 DNA samples from 22q11DS-affected families. A total of 219 (56%) individuals with 22q11DS had maternal origin and 170 (44%) had paternal origin of the de novo deletion, which represents a statistically significant bias for maternal origin (p = 0.0151). Combined with many smaller, previous studies, 465 (57%) individuals had maternal origin and 345 (43%) had paternal origin, amounting to a ratio of 1.35 or a 35% increase in maternal compared to paternal origin (p = 0.000028). Among 1,892 probands with the de novo 22q11.2 deletion, the average maternal age at time of conception was 29.5, and this is similar to data for the general population in individual countries. Of interest, the female recombination rate in the 22q11.2 region was about 1.6-1.7 times greater than that for males, suggesting that for this region in the genome, enhanced meiotic recombination rates, as well as other as-of-yet undefined 22q11.2-specific features, could be responsible for the observed excess in maternal origin.

Association of IL-12p70 and IL-6:IL-10 ratio with autism-related behaviors in 22q11.2 deletion syndrome: a preliminary report.

22q11.2 deletion syndrome (22q11DS) is a genetic disorder that conveys a significant risk for the development of social behavior disorders, including autism and schizophrenia. Also known as DiGeorge syndrome, 22q11DS is the second most common genetic disorder and is characterized by an elevated risk for immune dysfunction, up to 77% of individuals have an identifiable immune deficiency. We hypothesize that this immune dysfunction could contribute to the elevated risk of impaired social behavior seen in 22q11DS. The current study begins to elucidate these immune deficits and link them with the behavioral alterations associated with the disorder. Serum concentrations of a series of cytokines were examined, using a multiplex immunoassay, in sixteen individuals with 22q11DS and screened for autism-related behavior using the Autism Diagnostic Interview-Revised (ADI-R). This preliminary study examined correlations between specific immune proteins and each of the ADI-R algorithm scores (social, communication, and repetitive behavior). The inflammatory cytokine IL-1ß, as well as the ratio between the inflammatory cytokine IL-6 and the anti-inflammatory cytokine IL-10, were correlated with social scores (r=0.851, p=0.004; r=0.580, p=0.018). In addition, the inflammatory cytokines interferon gamma and IL-12p70 were correlated with repetitive behaviors (r=0.795, p=0.033; r=0.774, p=0.002). Interestingly, IL-12 has been reported to be increased in autistic children. These data show a positive association between severity of autism-related behaviors and level of serum concentrations of inflammatory cytokines in individuals with 22q11DS, providing a basis for further inquiry.

Overt cleft palate phenotype and TBX1 genotype correlations in velo-cardio-facial/DiGeorge/22q11.2 deletion syndrome patients.

Velo-cardio-facial syndrome/DiGeorge syndrome, also known as 22q11.2 deletion syndrome (22q11DS) is the most common microdeletion syndrome, with an estimated incidence of 1/2,000-1/4,000 live births. Approximately 9-11% of patients with this disorder have an overt cleft palate (CP), but the genetic factors responsible for CP in the 22q11DS subset are unknown. The TBX1 gene, a member of the T-box transcription factor gene family, lies within the 22q11.2 region that is hemizygous in patients with 22q11DS. Inactivation of one allele of Tbx1 in the mouse does not result in CP, but inactivation of both alleles does. Based on these data, we hypothesized that DNA variants in the remaining allele of TBX1 may confer risk to CP in patients with 22q11DS. To test the hypothesis, we evaluated TBX1 exon sequencing (n = 360) and genotyping data (n = 737) with respect to presence (n = 54) or absence (n = 683) of CP in patients with 22q11DS. Two upstream SNPs (rs4819835 and rs5748410) showed individual evidence for association but they were not significant after correction for multiple testing. Associations were not identified between DNA variants and haplotypes in 22q11DS patients with CP. Overall, this study indicates that common DNA variants in TBX1 may be nominally causative for CP in patients with 22q11DS. This raises the possibility that genes elsewhere on the remaining allele of 22q11.2 or in the genome could be relevant.

Chromosome 22q11.2 deletion syndrome in African-American patients: a diagnostic challenge.

Chromosome 22q11.2 deletion syndrome (22q11DS) is associated with numerous and variable clinical manifestations including conotruncal heart abnormalities, palatal anomalies, hypoparathyroidism, immune deficiency, and cognitive deficits. The clinical suspicion of this syndrome is often heightened by the presence of characteristic facial features. A previous report highlighted the under-diagnosis of this condition in African Americans, thought to be related to a paucity of typical facial features. We ascertained the largest cohort (n = 50) of African-American individuals with 22q11DS reported thus far, across five genetics centers in the United States and report on their facial and other phenotypic features. About 3/4 of our cohort has at least one dysmorphic facial feature. Auricular abnormalities, especially small ears, are the most common dysmorphic facial feature followed by nasal and ocular abnormalities. Skeletal findings are seen in about 2/3 of our cohort, higher than the typical frequency reported in 22q11DS. Cardiac anomalies, developmental delay, and palatal abnormalities are seen at a lower frequency in our cohort. Thus, it is evident that the features traditionally associated with 22q11DS are difficult to recognize in African-American individuals with this syndrome, due to both altered frequencies of major anomalies and a non-classic facial appearance. Therefore, a high index of suspicion is needed to recognize 22q11DS in African-American individuals.

Genotype and cardiovascular phenotype correlations with TBX1 in 1,022 velo-cardio-facial/DiGeorge/22q11.2 deletion syndrome patients.

Haploinsufficiency of TBX1, encoding a T-box transcription factor, is largely responsible for the physical malformations in velo-cardio-facial /DiGeorge/22q11.2 deletion syndrome (22q11DS) patients. Cardiovascular malformations in these patients are highly variable, raising the question as to whether DNA variations in the TBX1 locus on the remaining allele of 22q11.2 could be responsible. To test this, a large sample size is needed. The TBX1 gene was sequenced in 360 consecutive 22q11DS patients. Rare and common variations were identified. We did not detect enrichment in rare SNP (single nucleotide polymorphism) number in those with or without a congenital heart defect. One exception was that there was increased number of very rare SNPs between those with normal heart anatomy compared to those with right-sided aortic arch or persistent truncus arteriosus, suggesting potentially protective roles in the SNPs for these phenotype-enrichment groups. Nine common SNPs (minor allele frequency, MAF > 0.05) were chosen and used to genotype the entire cohort of 1,022 22q11DS subjects. We did not find a correlation between common SNPs or haplotypes and cardiovascular phenotype. This work demonstrates that common DNA variations in TBX1 do not explain variable cardiovascular expression in 22q11DS patients, implicating existence of modifiers in other genes on 22q11.2 or elsewhere in the genome.

Observation and prediction of recurrent human translocations mediated by NAHR between nonhomologous chromosomes.

Four unrelated families with the same unbalanced translocation der(4)t(4;11)(p16.2;p15.4) were analyzed. Both of the breakpoint regions in 4p16.2 and 11p15.4 were narrowed to large ∼359-kb and ∼215-kb low-copy repeat (LCR) clusters, respectively, by aCGH and SNP array analyses. DNA sequencing enabled mapping the breakpoints of one translocation to 24 bp within interchromosomal paralogous LCRs of ∼130 kb in length and 94.7% DNA sequence identity located in olfactory receptor gene clusters, indicating nonallelic homologous recombination (NAHR) as the mechanism for translocation formation. To investigate the potential involvement of interchromosomal LCRs in recurrent chromosomal translocation formation, we performed computational genome-wide analyses and identified 1143 interchromosomal LCR substrate pairs, >5 kb in size and sharing >94% sequence identity that can potentially mediate chromosomal translocations. Additional evidence for interchromosomal NAHR mediated translocation formation was provided by sequencing the breakpoints of another recurrent translocation, der(8)t(8;12)(p23.1;p13.31). The NAHR sites were mapped within 55 bp in ∼7.8-kb paralogous subunits of 95.3% sequence identity located in the ∼579-kb (chr 8) and ∼287-kb (chr 12) LCR clusters. We demonstrate that NAHR mediates recurrent constitutional translocations t(4;11) and t(8;12) and potentially many other interchromosomal translocations throughout the human genome. Furthermore, we provide a computationally determined genome-wide "recurrent translocation map."

Do neonates with genetic abnormalities have an increased morbidity and mortality following cardiac surgery?

INTRODUCTION: Genetic abnormalities occur in approximately 20% of children with congenital heart disease. The purpose of this study was to evaluate the effect of genetic abnormalities on short-term outcomes following neonatal cardiac surgery. METHODS: Retrospective review of all neonates (n = 609) undergoing cardiac surgery from January 2003 to December 2006. Genetic abnormalities were identified in 93 neonates (15%). Genetic abnormalities identified were 22q11.2 deletion (23), chromosomal abnormalities including various monosomies, trisomies, deletions, duplications, and inversions (17), dysmorphic undefined syndrome without recognized chromosomal abnormality (27), Down syndrome (9), laterality sequences (9), recognixed syndromes and genetic etiology including Mendelian (i.e. Alagille, CHARGE) (8). RESULTS: Neonates with genetic abnormalities had lower birth weights and were older at time of surgery. There was no difference in operative variables, duration of mechanical ventilation or ICU length of stay between the two groups. There was an increase in total hospital length of stay and postoperative complications in the neonates with genetic abnormalities. Importantly, in hospital mortality was not different. CONCLUSION: Neonates with genetic abnormalities have a higher risk of postoperative complications and a longer hospital length of stay. However, there is no increase in hospital mortality. This information may aid in patient management decisions and parental counseling. Longer-term studies are needed for understanding the total impact of genetic abnormalities on neonates with congenital heart disease.

Preaxial hallucal polydactyly as a marker for diabetic embryopathy.

BACKGROUND: Diabetes is the most common endocrinologic complication during pregnancy, and poor control can lead to a variety of congenital anomalies in the fetus. However, it is often difficult to differentiate between diabetes-related anomalies and an underlying genetic syndrome. In the 1990s it was proposed that preaxial hallucal polydactyly, particularly when proximally placed, was a distinguishing feature of diabetic embryopathy. METHODS: We summarize the clinical findings in 18 patients (five previously reported in abstract form) with diabetic embryopathy and preaxial hallucal polydactyly to determine which features are most suggestive of diabetic embryopathy. RESULTS: All 18 patients had preaxial hallucal polydactyly (seven bilateral, 11 unilateral), of which 15 patients had proximal implantation of the extra hallux. Further skeletal findings included the following: segmentation anomalies of the spine, equinovarus deformity of the feet, tibial hemimelia, hip dysplasia, and femoral hypoplasia. Upper limb malformations were rare. Eleven of the 18 mothers had prepregnancy insulin-dependent diabetes, while one mother had prepregnancy type 2 diabetes that required insulin therapy in the 3(rd) trimester. Five mothers had gestational diabetes that required insulin and one mother had gestational diabetes that was controlled by diet. The majority of mothers had poorly controlled diabetes during the pregnancy. CONCLUSIONS: Proximally placed preaxial hallucal polydactyly, particularly when coupled with segmentation anomalies of the spine and tibial hemimelia, is highly suggestive of diabetic embryopathy. Varying degrees of diabetes in the mothers point to a possible genetic predisposition interacting with the teratogenic effects of poor glycemic control leading to specific limb anomalies.

Sclerocornea associated with the chromosome 22q11.2 deletion syndrome.

Reported ocular findings in the 22q11.2 deletion syndrome (which encompasses the phenotypes of DiGeorge, velocardiofacial, and Takao (conotruncal-anomaly-face) syndromes) have included posterior embryotoxon (prominent, anteriorly displaced Schwalbe's line at the corneal limbus or edge), retinal vascular tortuosity, eyelid hooding, strabismus, and astigmatism. We present seven 22q11.2 patients from multiple centers with sclerocornea, an eye finding previously unreported in the literature. Four boys and three girls were identified with sclerocornea, systemic DGS/VCFS findings, and fluorescence in situ hybridization (FISH)-confirmed microdeletion at chromosome 22q11.2. FISH diagnosis was perinatal in six patients but at 2 years of age in one child. Sclerocornea was bilateral in five patients. Findings included descemetocele (five eyes), microophthalmos (one eye), iridocorneal adhesions (one bilateral case), and severe anterior segment dysgenesis (one eye). Two patients underwent bilateral corneal transplantation; another two were scheduled for possible unilateral transplant. Sclerocornea is a static congenital condition in which the cornea is opaque and vascularized and resembles the sclera. The novel finding of sclerocornea suggests that a genetic locus at 22q11.2 may be involved in anterior segment embryogenesis. In most of our patients, the diagnostic process was underway, but in one patient 22q11.2 deletion was not suspected until after the child had already been undergoing treatment for sclerocornea for 2 years. Sclerocornea should be added to the clinical manifestations of the 22q11.2 deletion syndrome. Ophthalmologists diagnosing sclerocornea in children with systemic findings suggestive of 22q11.2 deletion should ensure appropriate genetic referral.