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Full expression of Hunter's disease in a female with an X‐chromosome deletion leading to non‐random inactivation
Author(s) -
Broadhead D. M.,
Kirk Jean M.,
Burt A. J.,
Gupta Vidya,
Ellis Patricia M.,
Besley G. T. N.
Publication year - 1986
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.1986.tb01896.x
Subject(s) - genetics , x chromosome , biology , chromosome , x inactivation , gene
A 2.5‐year‐old girl who presented with abdominal distension, hepatomegaly, coarse fades, hirsutism and contraction deformities was investigated for mucopolysaccharidoses. Urinary excretion showed increased total glycosaminoglycans (105 mg/mmol creatinine; normal for age 9–20 mg/mmol) with marked increases of dermatan and heparan sulphates. A number of lysosomal enzyme activities were measured on leucocytes, serum and cultured fibroblasts. Normal or high activities were found for a‐iduronidase, N‐acetylgalactosamine‐6‐sulphatase, β‐galactosidase, arylsulphatase B and /J‐glucuronidase. However a marked deficiency ofiduronate sulphate sulphatase activity was observed, consistent with a diagnosis of Hunter's disease. Activities were reduced to less than 2% of mean control values in the patient's leucocytes, serum and cultured fibroblasts. Normal activities were measured in samples from the father and younger sister but a partial deficiency (43% of control serum) was found in the mother. Chromosome studies on the patient revealed a partial deletion of the long arm of one X‐chromosome, most probably of band Xq25, which was not inherited from either parent. Studies using BrdU indicated that the deleted X chromosome was consistently late replicating, and as a result the Hunter gene was fully expressed on the other X chromosome.