281- What are the differences in patients with classical and mosaic Turner
syndrome?
The differences in patients with classical and mosaic Turner syndrome are sum-
marized in the table given below.Parameters Classical Turner Mosaic Turner
Karyotype 45,XO 45,XO/46,XX (most common)
Incidence 50–60 % 20–30 %
Height Severe short stature Mildly affected
Phenotypic abnormalities Severe Mild
Cardiac abnormalities 30–39 % 24 %
Renal abnormalities 46 % 39 %
Gonadal function Invariably affected Spontaneous puberty 30 %
Menarche 10 %
Fertility 2–3 %
Mortality High (SMR 4.4) Low (SMR 2.2)- What are the disorders which share phenotypic features of Turner syndrome?
Individuals with Noonan’s syndrome and mixed gonadal dysgenesis share sev-
eral phenotypic features of Turner syndrome like short stature, webbing of
neck, low posterior hairline, and cardiac and renal anomalies. In addition,
patients with Leri–Weil dyschondrosteosis also share many characteristic skel-
etal manifestations of Turner syndrome including short stature, cubitus valgus,
short fourth metacarpal and high-arched palate.- What are the differences between Turner syndrome and Noonan’s syndrome?
Although both Turner syndrome and Noonan’s syndrome share several pheno-
typic features like short stature, cubitus valgus, low-set ears, low posterior hair-
line, and malformed ears and ptosis, there are several differences between these
disorders, which are summarized in the table given below.Characteristics Turner syndrome Noonan’s syndrome
Gender Only females Both sexes
Inheritance Sporadic Autosomal dominant/sporadic
Karyotype 45,XO Normal
45,XO/46,XX
Cardiac defects Left sided Right sided
Bicuspid aortic valve Pulmonary stenosis
Coarctation of aorta Hypertrophic cardiomyopathy
Gonadal function Ovarian failure invariable Females: normal
Males: cryptorchidism, delayed puberty,
infertility
Mental
retardationAbsent 25 %
Mild learning disabilities +8 Turner Syndrome