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with Turner syndrome have 45XO karyotype, whereas mosaic forms (45XO/46XX)
contribute approximately to 25 % of cases, and the rest have structural abnormalities
of X chromosome (e.g., long-arm or short-arm deletion, isochromosome, or ring
chromosome). Patients with deletion of short arm of X chromosome (Xp-) predomi-
nantly present with growth failure, while those with long-arm involvement (Xq-)
have ovarian failure as the presenting manifestation. Further, patients with ring chro-
mosome usually have mental retardation and those with isochromosome have associ-
ated autoimmune disorders. Although our patient had isochromosome, she did not
have autoimmune thyroid disease or celiac disease. The aims of treatment in a patient
with Turner syndrome are to improve the adult height potential, timely induction and
maintenance of secondary sexual characteristics, and appropriate management of
comorbidities like cardiovascular, renal, and otological disorders. The index patient
was initiated with low-dose estradiol valerate. Delaying the induction of puberty
beyond 12 years of age is not recommended as this may adversely affect psychoso-
cial development and bone health of the child. Further, there is evidence to support
that estradiol when initiated at low doses at 12 years of age and slowly built-up there-
after allows normal pubertal development without influencing the adult height poten-
tial of the child. Progesterone should be added cyclically, either after the onset of
breakthrough bleed or 2 years after the initiation of estrogen therapy. The rhGH
therapy in children with Turner syndrome is rewarding if initiated at the onset of
growth faltering, and it can be started as early as 9 months of age. The index patient
had bone age of 12 years and did not have epiphyseal fusion; therefore, rhGH therapy
may still be effective in terms of final adult height gain.
8.3 Clinical Rounds
- What is Turner syndrome?
Turner syndrome (TS) is a chromosomal disorder characterized by short stat-
ure, gonadal failure, and typical physical features in a phenotypic female with
loss of either entire X chromosome or complete/partial loss of short arm (p) of
X chromosome.
- Who should not be considered to have Turner syndrome despite the deletion of
X chromosome?
Deletion of a part of X chromosome distal to Xq24 is associated with gonadal
failure; however, these individuals do not have characteristic phenotypic fea-
tures of Turner syndrome and hence not considered to have Turner syndrome.
Patients with small distal short-arm deletions (Xp-) with intact Xp22.3 have
many characteristic skeletal abnormalities of Turner syndrome, but have a low
risk of gonadal failure; hence, they are also not considered to have Turner syn-
drome. Individuals with a male phenotype are also not considered to have
Turner syndrome, regardless of the karyotype.
8 Turner Syndrome