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Summary: A case with 46,XX,del(ll)lq23.2) karyotype and poor vision with literature review: Here we describe clinical and cytogenetic data on a female child whom had been referred to our laboratory suspected to have Turner syndrome since she had webbed neck. Cytogenetic analysis revealed that she had deletion at 1 Iq23.2 to I lq terminal so her karyotype was ascertained as 46,XX,del( 11 >(q23.2). Her parents had normal karyotypes. In addition to many clinical features of del( 11 q ) syndrome the case had poor vision which is not common for this syndrome. Clinical features of this case and a few published cases will be reviewed briefly.
Key-words: 11q terminal deletion disorder - Turner syndrome - Poor vision.
INTRODUCTION
The 1 lq terminal deletion disorder (previously called Jacobsen syndrome) is a recognized pattern of malformation caused by terminal deletion of the long (q) arm of chromosome 11 typically from band 11q23 to the telomere (1). Jacobsen (1 lq-) syndrome is a rare genetic disease (~1 in 100 000 live births). The subsequent loss of a large number of genes results in a complex and varied phenotype (1 ).
Characteristic clinical signs include mild to moderate psychomotor retardation, failure to thrive, trigonocephaly, hypertelorism, wide or low nasal bridge, low-set malformed ears, microretrognathia, cardiac defects, digital anomalies, and thromboor pancytopenia (11,14).
The human autosomal dominant nonsyndromic deafness DFNA12 has been mapped to a 36-cM interval on 1 Iq22-q24, between Dl 1S4I20 and Dl 1S912. Affected individuals display mild to moderately severe bilateral sensorineural hearing loss, mainly in the middle frequencies (500-2000 Hz) with a prelingual onset. Dl 1S925 maps in the middle of this region, cosegregating with DFNA12 in this pedigree.
There is a gene called TECTA gene (tectorin alpha) which is located on II q22-q24 provides instructions for making a protein called alpha-tectorin. This protein is found in the inner ear, as part of a structure called the tectorial membrane. The tectorial membrane helps to convert sound waves to nerve impulses, a critical process for normal hearing.
Alpha-tectorin interacts with other proteins to form the tectorial membrane. Two regions of the alpha-tectorin protein, called the vWFD domain and the zona pellucida domain, are important for protein interactions and assembly of the tectorial membrane.
It has...