"CATCH 22" sans cardiac anomaly, thymic hypoplasia, cleft palate, and hypocalcaemia: cAtch 22. A common result of 22q11 deficiency?

Syndrome de Di George, étude rétrospective de 52 cas

The deletion of chromosome 22q11.2 is involved in the majority of DiGeorge or velo-cardiofacial syndrome. The phenotypic variability was noted in the "CATCH 22" acronym. This acronym doesn't recapitulate the full spectrum of the symptoms. The diagnosis of this syndrome can be done with the prenatal diagnosis, with fetal pathology or with a child alive.

METHODS

Review of 52 cases with the microdeletion 22q11. Six cases were diagnosed during the prenatal period, 12 cases at fetal pathology examination, and 34 cases during infancy.

RESULTS

Cardiac malformations were the major indications (75%) to search for the microdeletion. The facial dysmorphy was difficult to diagnose during the antenatal period or in dead foetus, thereby it was not often recognized. The renal anomalies usually present in 35% of cases, were diagnosed in only 6 to 16% of the cases in our study.

CONCLUSION

Phenotypic diversity of the DiGeorge syndrome is important. Its knowledge allows to better determine the indications of the research of the microdeletion. 22q11.2.

Three new patients with congenital unilateral facial nerve palsy due to chromosome 22q11 deletion

We report three unrelated patients with congenital facial nerve palsy and chromosome 22q11 deletion, a condition hitherto poorly recognized. In the first case, facial palsy was associated with aortic coarctation, ductus arteriosus, and ostium secundum atrial septal defect. In the second case, facial palsy was associated with ostium secundum atrial septal defect, obstruction of the ureteropelvic junction, double ureteropelvic-calicial system, and distal metaphyseal widening of the forearm and leg bones. In both cases, facial palsy was the presenting feature. In the third case, an ostium secundum atrial septal defect was also present, but involvement of cranial nerves III, VI, and VIII, in addition to hypoplastic structures of cerebellar and cerebral peduncles, were the predominant features. There were no inherited deletions within chromosome band 22q11 and the de novo deletions detected in each case belonged to the paternally derived chromosome 22. Association of facial nerve palsy and congenital heart disease versus cardiofacial syndrome are different only on clinical grounds, so both conditions can be genetically identical and form part of the spectrum of defects associated with chromosome 22q11 deletions. We recommend investigation for chromosome 22q11 deletions in patients with complete nerve facial palsy.

22q11.2 microdeletions in adults with familial tetralogy of Fallot

PURPOSE

To determine the incidence of 22q11.2 microdeletions in the adult survivors of correction of tetralogy of Fallot who have familial congenital heart disease.

METHODS

Patients who had survived a correction of tetralogy of Fallot between 1954 and 1974 and had affected family members were identified during a study of these long-term survivors. Fluorescence in situ hybridization analysis was performed using both the N 25 (Oncor) and TUPLE1(VYSIS) probes, mapped to 22q11.2.

RESULTS

One of 18 (5.6%) patients had a microdeletion within 22q11.2, including both N25 and TUPLE1.

CONCLUSION

22q11.2 microdeletions involving TUPLE1 and/or N25 are present in a minority of adults with familial tetralogy of Fallot.

A population study of chromosome 22q11 deletions in infancy

AIMS

To determine the prevalence of submicroscopic deletions within chromosome band 22q11 in infants with significant heart disease and compare this with the prevalence of other chromosomal abnormalities causing significant heart disease. To determine a minimum prevalence of deletions within chromosome band 22q11 in infants in the general population.

METHODS

Chromosome analysis was performed on samples from infants born in the former UK Northern Health Region in 1994 and 1995 who either had significant heart disease or who were suspected to have a chromosome band 22q11 deletion following referral to the Northern Genetics Service. Significant heart disease was defined as major structural malformation or cases where invasive investigation or intervention was required in infancy.

RESULTS

Chromosome band 22q11 deletions were identified in nine infants in a population of 69,129 livebirths, giving a minimum prevalence of 13 per 100,000 (95% confidence interval 4.5 to 21.5). Six cases had significant heart disease, one of whom died before diagnosis. In the same population there were 53 cases of trisomy 21, 15 of whom had significant heart disease.

CONCLUSION

The most common chromosomal cause of significant congenital heart disease remains trisomy 21, while the second most common chromosomal cause is deletion in chromosome band 22q11.

Spectrum of clinical features associated with interstitial chromosome 22q11 deletions: a European collaborative study

We present clinical data on 558 patients with deletions within the DiGeorge syndrome critical region of chromosome 22q11. Twenty-eight percent of the cases where parents had been tested had inherited deletions, with a marked excess of maternally inherited deletions (maternal 61, paternal 18). Eight percent of the patients had died, over half of these within a month of birth and the majority within 6 months. All but one of the deaths were the result of congenital heart disease. Clinically significant immunological problems were very uncommon. Nine percent of patients had cleft palate and 32% had velopharyngeal insufficiency, 60% of patients were hypocalcaemic, 75% of patients had cardiac problems, and 36% of patients who had abdominal ultrasound had a renal abnormality. Sixty-two percent of surviving patients were developmentally normal or had only mild learning problems. The majority of patients were constitutionally small, with 36% of patients below the 3rd centile for either height or weight parameters.

Idiopathic thrombocytopenic purpura in two mothers of children with DiGeorge sequence: a new component manifestation of deletion 22q11?

The phenotypic spectrum caused by the microdeletion of chromosome 22q11 region is known to be variable. Nearly all patients with DiGeorge sequence (DGS) and approximately 60% of patients with velocardiofacial syndrome exhibit the deletion. Recent papers have reported various congenital defects in patients with 22q11 deletions. Conversely, some patients have minimal clinical expression. Ten to 25% of parents of patients with DGS exhibit the deletion and are nearly asymptomatic. Two female patients carrying a 22q11 microdeletion and presenting with idiopathic thrombocytopenic purpura are reported. Both had children with typical manifestations of DGS.

Submicroscopic deletion in chromosome 22q11 in trizygous triplet siblings and their father. Clinical variability of 22q11 deletion

A submicroscopic deletion of chromosome 22q11 was demonstrated in three triplets and in their father. Two children had the typical DiGeorge sequence with at least three of the four cardinal features: conotruncal heart disease, hypoplastic thymus and typical facial features. Hypoparathyroidism was present in one of them. The third child had features of both DiGeorge and velo-cardio-facial syndrome (VCFS). The father presented with features compatible with VCFS. This observation further illustrates the wide variability in expression of a submicroscopic deletion of 22q11, even within one family.

Anal anomalies: an uncommon feature of velocardiofacial (Shprintzen) syndrome?

We report three cases of velocardiofacial syndrome (VCFS) with anal anomalies who have deletions of the 22q11 region and a further case where the proband has VCFS clinically and her father has an anal anomaly. It is important to consider VCFS in the differential diagnosis of children with anal anomalies and to look for other features of the syndrome, such as asymmetrical crying facies, submucous cleft of the palate, developmental delay, cardiac anomalies, and hypoparathyroidism.

[Microdeletion of the chromosome 22q11 in children: apropos of a series of 49 patients]

Most of the children with Di George syndrome and 60% of patients with velocardiofacial syndrome exhibit a microdeletion within chromosome 22q11. The phenotypic expression of this chromosomal abnormality is highly variable.

PATIENTS

Forty-nine children, 0 to 15 years of age, were demonstrated as carriers of a 22q11 microdeletion. The main referral diagnoses were: Di George syndrome (19 cases), velocardiofacial syndrome (14 cases); congenital heart defect with dysmorphism (9 cases); hypoparathyroidism (2 cases). The microdeletion was detected by fluorescent in situ hybridization with probes specific of the 22q11 region.

RESULTS

Facial dysmorphism was the only constant feature. A congenital heart defect was present in 84% of cases. Significant hypocalcemia was documented in 51% of cases and thymic hypo or agenesis in 83%. Significant immune deficiency was documented in nine cases. The most frequent associated defects were urinary tract malformations (8 cases). A cleft palate was present in height enfants but velopharyngeal insufficiency was almost constant. Two-thirds of children had psychomotor delay, and five children exhibited behavioral problems. Of the 35 couples of parents tested, eight mothers were found to be carriers of the deletion.

CONCLUSION

For the pediatrician, it is essential to know the variability of the clinical picture. The long-term prognosis is conditioned by the possibility of mental retardation and learning disabilities. Parents should be tested for the presence of the deletion. The occurrence of the microdeletion in asymptomatic relatives raises difficult problems in genetic counselling.

Monozygotic twins with chromosome 22q11 deletion and discordant phenotype

We report monozygotic twins concordant for 22q11.2 deletion but discordant for clinical phenotype. Both boys show the typical dysmorphic features with short palpebral fissures, square nasal tip, small mouth, and both have nasal speech, but only one twin had a heart defect. They show that the phenotypic variability seen in this microdeletion syndrome cannot be explained on the basis of genotypic differences alone.

Idiopathic hypoparathyroidism in two patients with 22q11 microdeletion

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