Upper limb malformations in DiGeorge syndrome

Sprengel anomaly in deletion 22q11.2 (DiGeorge/Velo-Cardio-Facial) syndrome

Sprengel anomaly (SA) is a rare skeletal defect characterized by uni- or bi-lateral elevation of the scapula. This anomaly is often isolated, although it can occur in association with other defects, including cervical spine malformations, cleft palate, and facial anomalies. Neural crest migration anomalies have been involved in the etiology of SA. Since the same embryological pathway accounts for some of the clinical features of deletion 22q11.2 syndrome (del22q11.2; DiGeorge/Velo-Cardio-Facial syndrome), we investigated the occurrence of SA in a consecutive series of 235 del22q11.2 patients aged more than 2 years, undergoing a complete clinical and orthopedic assessment of the dorsal and thoracic skeleton. In the present series, two patients were diagnosed with true SA. Present results and published reports suggest that scapular involvement including SA occurs in 1-2% of del22q11.2 individuals. Accordingly, this anomaly should be investigated as one of the possible skeletal findings of del22q11.2 syndrome, while this diagnosis should be excluded in patients presenting with SA associated with other defects.

[Hand and endocrine diseases]

The whole of hormones likely influence state of hands, modifying colouring and trophicity of the skin and having influence on its muscular, tendineous, osseous, articular components. Thus state of the hands contributes to the recognition of the endocrine diseases: hot and moist hands of the Graves' disease, dry, cold and infiltrated hands in myxoedema, pale and fine hands of hypopituitarism, broad and thick hand of acromegaly, brachymetacarpia in the pseudohypoparathyroidism… Diabetes exposes particularly to tendineous and articular retractions, to whitlows and ungual mycosis.

Craniosynostosis and radial ray defect: a rare presentation of 22q11.2 deletion syndrome

A newborn with bilateral coronal craniosynostosis, hypoplastic thumbs, imperforate anus, and prenatal growth restriction was evaluated and given the clinical diagnosis of Baller-Gerold syndrome (BGS). While confirmatory testing of RECQL4 was pending, the infant developed unexplained hypocalcemia, prompting testing for a 22q11.2 deletion. Subsequently, the infant was found to have a 22q11.2 deletion, and was negative for an RECQL4 mutation. We therefore conclude that 22q11.2 deletion syndrome can present with findings resembling the BGS phenotype.

Genetic counseling for the 22q11.2 deletion

Because of advances in palliative medical care, children with the 22q11.2 deletion syndrome are surviving into adulthood. An increase in reproductive fitness will likely follow necessitating enhanced access to genetic counseling for these patients and their families. Primary care physicians/obstetric practitioners are in a unique position to identify previously undiagnosed patients as they reach reproductive age and to refer them for genetic counseling. To date, most deletions are de novo, secondary to homologous recombination between low-copy repeat sequences located within 22q11.2. Nonetheless, both somatic and germ line mosaicism has been observed giving unaffected parents a small risk of recurrence. Once present though there is a 50% chance for a person with this contiguous deletion to have an affected child. With this in mind, a variety of prenatal monitoring techniques, as well as, preimplantation genetic diagnosis are available depending on the specific level of risk.

22q11 deletion syndrome and limb anomalies: report on two Brazilian patients

OBJECTIVE

To report on two Brazilian patients with chromosome 22q11 deletion who presented with velopharyngeal insufficiency, congenital heart anomalies, developmental delay, and limb anomalies. The pattern of limb anomalies in these patients, which range from ectrodactyly to limb synostosis, is very uncommon in 22q11 deletion syndrome.

CONCLUSION

These patients widen the spectrum of clinical signs of the 22q11 deletion syndrome and alert researchers to conduct additional investigation in patients with limb involvement with velopharyngeal insufficiency and/or cardiac anomalies, along with developmental delay.

Bifid tongue: a rare feature associated with infants of diabetic mother syndrome

Infants born to diabetic mothers (IDM) are well documented to have a higher rate of congenital malformations. Sacral agenesis/hypogenesis and caudal dysgenesis are classically linked to maternal diabetes, but many other types of anomalies are more frequent. In this case report, we describe a male infant born to a diabetic mother who in addition to other typical congenital abnormalities was born with an impressive bifid tongue. Accompanying congenital anomalies include unilateral microphthalmia, bilateral microtia, cleft palate, micropenis with unilateral cryptorchidism, bilateral radial hypoplasia, unilateral pre-axial polydactyly, and mid-line central nervous system defects including arhinencephaly and pituitary hypoplasia. Review of the literature reveals an additional case of an infant with a bifid tongue born to a diabetic mother [Comess et al., 1969]. In conclusion, bifid tongue without oral hamartoma, a rare congenital anomaly, can be an associated finding in IDM.

Primary cellular immunodeficiencies

Genetic defects in T-cell function lead to susceptibility to infections or to other clinical problems that are more grave than those seen in disorders resulting in antibody deficiency alone. Those affected usually present during infancy with either common or opportunistic infections and rarely survive beyond infancy or childhood. The spectrum of T-cell defects ranges from the syndrome of severe combined immunodeficiency, in which T-cell function is absent, to combined immunodeficiency disorders in which there is some, but not adequate, T-cell function for a normal life span. Recent discoveries of the molecular causes of many of these defects have led to a new understanding of the flawed biology underlying the ever-growing number of defects. Most of these conditions could be diagnosed by means of screening for lymphopenia or for T-cell deficiency in cord blood at birth. Early recognition of those so afflicted is essential to the application of the most appropriate treatments for these conditions at a very early age. The latter treatments include both transplantation and gene therapy in addition to immunoglobulin replacement. Fully defining the molecular defects of such patients is also essential for genetic counseling of family members and prenatal diagnosis.

Chromosome 22q11 deletion syndrome: update and review of the clinical features, cognitive-behavioral spectrum, and psychiatric complications

In this contribution we review current knowledge of the chromosome 22q11 deletion syndrome, with special emphasis on the clinical characteristics, including physical features, cognitive-behavioral spectrum, and psychiatric complications.

Isolation and characterization of a novel gene from the DiGeorge chromosomal region that encodes for a mediator subunit

Hemizygous deletions on chromosome 22q11.2 result in developmental disorders referred to as DiGeorge syndrome (DGS)/velocardiofacial syndrome (VCFS). We report the isolation of a novel gene, PCQAP (PC2 glutamine/Q-rich-associated protein), that maps to the DiGeorge typically deleted region and encodes a protein identified as a subunit of the large multiprotein complex PC2. PC2 belongs to the family of the human Mediator complexes, which exhibit coactivator function in RNA polymerase II transcription. Furthermore, we cloned the homologous mouse Pcqap cDNA. There is 83% amino acid identity between the human and the mouse predicted protein sequences, with 96% similarity at the amino- and carboxy-terminal ends. To assess the potential involvement of PCQAP in DGS/VCFS, its developmental expression pattern was analyzed. In situ hybridization of mouse embryos at different developmental stages revealed that Pcqap is ubiquitously expressed. However, higher expression was detected in the frontonasal region, pharyngeal arches, and limb buds. Moreover, analysis of subjects carrying a typical 22q11 deletion revealed that the human PCQAP gene was deleted in all patients. Many of the structures affected in DGS/VCFS evolve from Pcqap-expressing cells. Together with the observed haploinsufficiency of PCQAP in DGS/VCFS patients, this finding is consistent with a possible role for this novel Mediator subunit in the development of some of the structures affected in DGS/VCFS.

Features of DiGeorge syndrome and CHARGE association in five patients

We report on five patients presenting with features of two congenital disorders, DiGeorge syndrome (DGS) and CHARGE association. CHARGE association is usually sporadic and its origin is as yet unknown. Conversely, more than 90% of DGS patients are monosomic for the 22q11.2 chromosomal region. In each of the five patients, both cytogenetic and molecular analysis for the 22q11.2 region were normal. In view of the broad clinical spectrum and the likely genetic heterogeneity of both disorders, these cases are consistent with the extended phenotype of either DGS without 22q11.2 deletion or CHARGE association, especially as several features of CHARGE association have been reported in rare patients with 22q11.2 deletion association phenotypes. On the other hand, these could be novel cases of an independent association involving a complex defect of neural crest cells originating from the pharyngeal pouches.

Radial aplasia and chromosome 22q11 deletion

We report on a neonate with deletion 22q11 (del22q11) presenting with facial dysmorphism, ocular coloboma, congenital heart defect, urogenital malformations, and unilateral radial aplasia. This malformation complex includes features frequently occurring in velocardiofacial syndrome as well as findings described in the CHARGE and VACTERL associations. To our knowledge, the present case is the first report of radial aplasia in del22q11. This observation further supports and extends the clinical variability of del22q11.

Skeletal anomalies and deformities in patients with deletions of 22q11

Skeletal anomalies in patients with a 22q11.2 deletion are reported infrequently. We report the skeletal findings in 108 patients with a 22q11.2 deletion, of whom 37 (36%) had a skeletal anomaly. Twenty-two patients (20%) had anomalies of the limbs, 7 of the upper limb, including preaxial or postaxial polydactyly. An anomaly of the lower limb was found in 16 patients, including postaxial polydactyly, clubfoot, severely overfolded toes, and 2-3 toe cutaneous syndactyly. Chest films of 63 patients were examined; 30% of them had abnormal findings, most commonly supernumerary ribs (17%) or a "butterfly" vertebral body (11%). Hypoplastic vertebrae, hemivertebrae, and vertebral coronal clefts were also noted. Thus, skeletal anomalies are not uncommon in patients with a 22q11.2 deletion and may occur more frequently than recognized previously.

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.

Chromosome 22q11 deletion presenting as the Potter sequence

A female fetus with the Potter sequence, caused by unilateral renal agenesis and contralateral multicystic renal dysplasia, was found to have a submicroscopic deletion in chromosome 22q11. The only associated anomaly was agenesis of the uterus and oviducts (Von Mayer-Rokitansky-Küster anomaly). The deletion was inherited from the father, who presented the typical velocardiofacial syndrome phenotype, but no urological anomalies. This observation further extends the clinical spectrum associated with a deletion in 22q11.

Limb anomalies in DiGeorge and CHARGE syndromes

Limb anomalies are not common in the DiGeorge or CHARGE syndromes. We describe limb anomalies in two children, one with DiGeorge and the other with CHARGE syndrome. Our first patient had a bifid left thumb, Tetralogy of Fallot, absent thymus, right facial palsy, and a reduced number of T-cells. A deletion of 22q11 was detected by fluorescence in situ hybridization (FISH). The second patient, with CHARGE syndrome, had asymmetric findings that included right fifth finger clinodactyly, camptodactyly, tibial hemimelia and dimpling, and severe club-foot. The expanded spectrum of the DiGeorge and CHARGE syndromes includes limb anomalies.

[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.