The proposita was a 3-year-old male born to non-consanguineous parents. The mother’s age was 27 years and father’s age was 32 years and there was no history of recurrent abortions. Weight, length and head circumference were 5 Kg, 56 cm, and 31 cm, respectively. Facies was dysmorphic and included hypertelorism, flat nasal bridge, micrognathia, short neck, low-set ears, crumpled right ear, and blind sinuses opening between angle of mouth and ear covered by skin tags. Left ear had two skin tags and three preauricular sinuses. Total palm length was 6 cm. Both knee and ankle joints were in flexion contracture. There was no hepato-splenomegaly and central nervous system was grossly normal on clinical examination. Cardiovascular examination revealed no aparent abnormality. Inspiratory stridor was present and ascribed due to laryngo-tracheomalacia. X-ray skull showed thining out of the calvarium with silver beaten appearence. CT-scan of the head showed no focal abnormality but there was dilatation of both the lateral ventricles along with the thinning of the cerebral cortex. Brainstem evoked response audiometry showed hearing deficiency. Biochemical invesigations showed elevated levels of phosphorous and alkaline phosphatase. Chromosomes from peripheral blood lymphocytes were studied using GTG-banding. Over one hundred metaphases were scored to rule out mosaicism. All cells demonstrated a modal number of 47 chromosomes with an extra chromosome 22. Chromosomal analysis of parents and other family members was found to be normal.

Trisomy 22 is extremely rare with an estimated incidence varying from 1 in 30,000 to 1 in 50,000 live births. Majority of non-mosaic trisomy 22 live-born children die-before one year of age(4). The oldest individual with trisomy 22 was a 20 year old(5). To the best of our knowledge present case is the second case of live-born non-mosaic trisomy 22 living beyond one year of age.

Clinical features reported to be common between complete and mosaic trisomy 22 include advanced parental age, small size for gestational age, microcephaly, epicanthic folds, micrognathia, malformed ears, con-genital heart defect and clinodactyly. How-ever, there are traits unique to each subtype. Early death, prematurity, hyper-telorism, flat nasal bridge and anomalous external genitalia are seen in trisomy 22; whereas, in mosaic trisomy 22 cases, hemiatrophy, mental retardation, growth retardation, dental anomaly, hearing loss and syndactyly are more frequent(3). The present case had most of the clinical features described, except advanced parental age, small gestational age, congenital heart disease and renal anomalies. Flexion contractures, as observed in our case are not described earlier. Recently, fluore-scence in situ hybridisation (FISH) and whole chromosome painting studies revealed that the partial trisomy 22 results from translocation between 22 and other chromo-somes, and also have some of the clinical features present in trisomy 22 children. In our case FISH study was not done due to unavailability of the technology.

Genetic counselling in such a family can be difficult and tricky. As both the parents in the present case had normal karyotypes, the risk seems to be extremely small but that also can be further minimized if the next pregnancy is properly supervised and a cytogenetic study can be done from the chorionic villi and amniotic fluid to rule out the remotest possibility of having such a child second time.

V. Babu Rao,
K. Seema,
K. Lily,
K. Ghosh,
D. Mohanty,
Institute of Immunohematology (ICMR),
13th Floor, KEM Hospital Campus,
Parel, Mumbai 400 012, India.
E-mail: [email protected]

1. Hassold T, Chen N, Funkhouser J, Joss T, Manuel B, Mastura J et al. A cytogenetic study of 1000 spontaneous abortions. Ann Hum Genet 1980, 44: 151-178.

2. Pridijan G, Gill W, Shapira E. Goldenhar sequense and mosaic trisomy. Am J Med Genet 1995; 59: 411-413.

3. Crowe CA, Shwartz S, Black CJ, Jaswaney V. Mosaic trisomy 22: A case presentation and literature review of trisomy 22 phenotypes. Am J Med Gen 1997, 71: 406-413.

4. Landonne JM, Gailard D, Carre-Pigeon F, Gabriel R. Fryns syndrome phenotype and trisomy 22. Am J Med Genet 1996, 61: 68-70.

5. Welter DA, Scharff III L, Teal NM, Thevaos TC. Trisomy 22 in a 20-year-old female. Hum Genet 1978, 43: 347-351.