CONCURRENCE OF Inv(7)(q11.2q32) AND Del(8)(p23.1) IN A GIRL WITH CONGENITAL MICROCEPHALY, HYPOTONIA, DEVELOPMENTAL DELAY, STRABISMUS, HYPERNATREMIA, HYPERMAGNESEMIA AND DEAFNESS
Mahjoubi, F., Nasiri, F., Razazian, F., Genetic Counseling
Summary: Concurrence ofinv(7)(qll.2q32) and del(8)(p23. 1) in a girl with congenital microcephaly, hypotonia, developmental delay, strabismus, hypernatremia, hypermagnesemia and deafness: The clinical manifestations and cytogenetic details of a de novo partial deletion of the short arm of chromosome 8, del(8Xp23.1), and inversion of long arm chromosome 7, inv(7)(ql 1.2q32), are described.
The case was a 22 month old girl referred to our cytogenetic laboratory due to many abnormal features such as congenital microcephaly, hypotonia, developmental delay, strabismus, highly arched palate, hypernatremia, hypermagnesemia and deafness. Chromosome analysis revealed 46,XX, inv(7)(qll.2q32),del(8)(p23.1) de novo karyotype. The concurrence of these two abnormalities has not been reported previously.
Key-words: del(8Xp23. 1 ) - inv(7)(q 1 1 .2q32) - Deafness
Since 1973, about thirty children have been reported with a partial deletion of 8p. The symptoms of the partial monosomy 8p may vary greatly in range and severity from case to case. However, common features include growth deficiency; mental retardation; craniofacial, microcephaly, epicanthal folds, cardiac abnormalities; and/or genital defects in affected males. Additional craniofacial features may also be present that tend to become less apparent with age, such as a short, broad nose; a low, wide nasal bridge; and/or micrognathia (4, 8, 18, 24). Further cases have had various unbalanced translocations with partial trisomies in addition to monosomy 8p.
Chromosomal inversions are one of the rarest chromosomal abnormalities with the frequency of 0.012% (14). So far only 7 cases of inversion chromosome 7 including 6 cases of inv 7q have been reported (1, 6,9,11,19,23).
Here we describe clinical and cytogenetic findings in a very unique case with both inv(7q) and del(8p).
A 22 month old girl was referred to our cytogenetic laboratory for chromosome study. She was the second child of unrelated parents. She has an elder healthy 4 year old sister. The pregnancy and delivery was uneventful. Her birth weight was 1700 gr and her height was 46 cm. The head circumference was 30 cm. Due to muscular hypotonia breast feeding could be started about a week after birth. At the age of 5 weeks she was admitted to hospital due to lung inflammation and infection. At the age of 5 months developmental delay was noted. She had gasten) reflection. She gained weight up to 5 months then it stopped.
At the time of examination (22 months), her weight was 6 kg, her height was 69 cm and the head circumference was 38 cm. She did not have the ability to sit or keep her neck and was generally developmentally delayed. She was restless and had sleeping problems overnight. She had normal vision but had strabismus with highly arched palate. She was completely deaf (by threshold ABR test) and therefore unspeakable (Fig. 1).
At the age of 12 months, T3, T4, TSH, and G6PD tests were normal. Amonia 163 mg/dl was above normal range (normal range less than 100). laxtate plasma was elevated 19.7 mg/dl (normal range 4.5-20). Serum Mg 2.5 mg/dl and sodium 157 meg/L were both above the normal range (normal range 1 .5-2.3 and 136-145 respectively). Serum calcium was 9.4 mg/dl (normal range 8.4-10.8).
Both Brain CT scan and MRI images were normal except that mucosal thickening of maxillary/ethmoid sinuses and mastoid air cells representing sino/mastoiditis was observed.
Mitotic cells were obtained from PHA stimulated peripheral blood lymphocytes metaphase according to standard protocols (2).
Briefly, peripheral blood lymphocytes were cultured in 5 ml RPMI 1640 (GIBCO), supplemented with 20% (v/v) fetal bovine serum (GIBCO) and 10 (xg/ml phytohaemagglutinin (GIBCO) at 37 °C. After 72 hrs of incubation 40 µ? colcemid (10 µg/ml, GIBCO) was added to the cells. The cells were incubated at 37 °C for about 10 mins. …