a patient with this condition is prone to develop infections due to poor t - cell formation and function . this rare syndrome results in hypocalcemia arising from parathyroid hypoplasia , thymic hypoplasia , and outflow tract defects of the heart . , we discuss the radiological features , laboratory findings , and the cytogenetic results that aided in the diagnosis of this rare syndrome . a 4-month - old infant presented with complaints of cough , cold , and breathlessness that had persisted for 2 days . initial clinical examination revealed bilateral wheeze on auscultation and subtle dysmorphic facial appearance which included small chin , small mouth , and coarse facial features . the mother also gave history of abortion of her previous pregnancy during the 2 trimester because of cardiac anomaly identified on fetal ultrasound ( usg ) scan . in view of its difficulty in breathing , the baby was admitted to the intensive care unit ( icu ) and was started on oxygen and nebulization . the baby was intubated and started on synchronized intermittent mandatory ventilation ( simv ) mode . chest radiograph frontal projection showed bilateral air space opacities with right upper lobe consolidation suggestive of pneumonia [ figure 1 ] . the baby was started on antibiotics and oral ribavirin . during the next day in icu , the child had seizures . biochemistry analysis showed reduced calcium level of 5.7 mg / dl ( normal value : 8.510.1 mg / dl ) . 25-hydroxy - vitamin d level was low and measured 13.4 ng / ml ( normal value : < 20 ng / ml ) . the parathyroid hormone ( pth ) level was normal in spite of the low calcium . blood investigations showed low hemoglobin measuring 7.5 g / dl ( normal value : 1114 g / dl ) and a total wbc count of 10,700 cells / ml . polymerase chain reaction ( pcr ) blood analysis showed positivity for cytomegalovirus ( cmv ) . flow cytometery of lymphocytes showed combined t - cell and b - cell immunodeficiency . in spite of good antibiotic cover and physiotherapy , intravenous immunoglobulin and steroids were started to treat persistent infection , following the hematologist 's advice . computed tomography ( ct ) of the chest with intravenous contrast showed hypoplastic thymus [ figure 2a ] and right upper lobe consolidation [ figure 2b ] . ct chest with maximum intensity projection ( mip ) and volume - rendered ( vr ) images showed aberrant right subclavian artery [ figure 3a and b ] . in view of dysmorphic facial features , chest infection , hypoplastic thymus , immunodeficiency , hypocalcemia , and decreased vitamin d , with a previous history of abortion of the fetus because of cardiac anomaly , a strong possibility of dgs was suspected . fluorescent in situ hybridization ( fish ) study was done to look for chromosomal defects . the results showed deletion of chromosome 22q11.2 [ figure 4 ] , which confirmed the diagnosis of this rare entity . the baby 's respiratory distress gradually settled and the infant was discharged on the parent 's request . ( a ) contrast - enhanced axial image of ct chest in mediastinal window shows absent thymus ( asterisk ) . ( b ) non - contrast axial image of ct chest in lung window shows consolidation involving the right upper lobe ( right arrow ) . ( a ) ct scan - coronal maximum intensity projection ( mip ) in arterial phase of chest shows aberrant right subclavian artery ( asterisk ) . ( b ) ct scan volume - rendered image shows aberrant right subclavian artery ( asterisk ) . fluorescent in situ hybridization ( fish ) study shows deletion of chromosome 22q11.2 ( arrow ) dgs is a primary immunodeficiency disease caused by deletion of genetic material from chromosome 22q11.2 . as part of this genetic defect , the thymus gland may be affected and this impairs the production of t - lymphocytes , which causes recurrent infections . the incidence of this rare syndrome was around 1 in 5000 births in the general population in the uk , according to the report of alison et al . more than 180 anomalies have been reported , so far ; the expression of dgs varies from person to person and a single affected individual will not have all the anomalies . the pathogenesis behind this rare entity is deletion of chromosome 22q11.2 , which causes third and fourth branchial pouch defects and may lead to hypoplasia or absence of thymus and/or parathyroid gland . dgs , in most instances , occurs sporadically and around 10% of the cases are inherited from one of the family members . the defective gene is autosomal dominant and there is 50% risk of transmitting the deletion to the child . the clinical features requiring the clinician to perform 22q11.2 deletion studies may vary from person to person depending on the age of the patient . the common classic findings include conotruncal cardiac anomalies ( i.e. , ventricular septal defect , tetralogy of fallot , vascular rings , and interrupted aortic arch ) , palatal abnormalities ( cleft palate and cleft lip ) , nasal regurgitation and/or hyper nasal speech , behavioral problems , psychiatric illness ( bipolar disorder or schizophrenia ) , immunodeficiency ( reduced t lymphocytes leading to recurrent infections ) , hypocalcemia , and characteristic facial features . radiological evaluation of a patient with suspected dgs includes evaluation of central nervous system , craniofacial abnormalities , musculoskeletal system , and cardiothoracic contents . a detailed evaluation of craniofacial system has to be done to check for external auditory canal ( eac ) stenosis , prominent nose , thin upper lip , and asymmetric face . ct with contrast of the head and neck is required to identify the presence of aberrant course of internal carotid arteries , hypoplastic adenoids , and middle ear anomalies . contrast - enhanced ct ( cect ) of the chest should be done to check for ventricular septal defect , tetralogy of fallot , aortic arch anomalies , vascular ring , absent thymus , and to identify lung infections . it is estimated that approximately 90% of patients with the clinical diagnosis of dgs have a deletion of a specific portion of chromosome number 22 at position 22q11.2 , called a microdeletion . approximately 90% of 22q11.2 deletions occur spontaneously and have not been passed on from the mother or father of the child . but once the diagnosis has been made , genetic counseling is critical and testing should be offered to parents and other family members . managing dgs needs a multidisciplinary approach and the cause for each symptom should be identified and treated accordingly . in our case , there was thymic hypoplasia ( as evident in ct imaging ) with decreased t lymphocyte production which , in turn , caused the b lymphocytes to produce insufficient antibodies ; hence , immunoglobulin therapy and antibiotics were administered . blood investigations revealed low calcium and vitamin d levels ; appropriate calcium and vitamin d supplements were administered . digeorge syndrome ( dgs ) is a rare genetic disorder which can cause a wide array of symptoms . the diagnosis is often missed or delayed because pregnant women are not routinely screened for this rare entity . hence , in any neonate with congenital hypocalcemia , recurrent infection , and seizure with absent parathyroid and thymus gland evident on imaging , a suspicion of dgs should arise and a detailed radiological , clinical , and cytogenetic examination should be carried out to avoid unnecessary complications .
digeorge syndrome is a congenital genetic disorder that affects the endocrine system , mainly the thymus and parathyroid glands . 
 the syndrome produces different symptoms , which vary in severity and character between patients . 
 it manifests with craniofacial dysmorphism and defects in the heart , parathyroid , and thymus . 
 patients can present with a palatal deformity and nasal speech . 
 this rare entity is caused mainly due to deletion of chromosome 22q11.2 . 
 radiographic evaluation of digeorge syndrome is necessary to define aberrant anatomy , evaluate central nervous system , craniofacial abnormalities , musculoskeletal system , and cardiothoracic contents . 
 it also helps in planning surgical procedures and surgical reconstructions . 
 we report a case of digeorge syndrome in a 4-month - old neonate and discuss the clinical , imaging , and cytogenetic findings that helped in the diagnosis of this rare entity .