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Images in Clinical Practice

Indian Pediatrics 2003; 40:431-432

Noonan Syndrome


Two siblings, a girl aged 16 years and a boy aged 14 years presented with short stature. On examination the height of the female child was 105 cms (<5th centile) and that of male child was 104 cms (<5th centile). Both children had typical leonin facies (prominent eyes, anteverted nares, antimongoloid slant, depressed nasal bridge and posteriorly placed prominent ears), low hair line, short and webbed neck, shield chest, small widely placed nipples, cubitus valgus with limited extension of the elbows, mild scoliosis, knock knee, flat feet (Figs 1 & 2). Boy had features of hypogonadism. Their mental development was normal and had satisfactory scholastic performance. Other systems were normal. These features are typical of those seen in Noonan syndrome.

Fig.1. A 14-year-old boy with Noonan syndrome and absence of breast development. Fig.2. A 16-year-old Girl with Noonan syndrome and absence of breast development.

Noonan syndrome is an autosomal dominant condition characterized by short stature, congenital heart defects (68%) (Pulmonic stenosis (50%), asymmetric septal hypertrophy (10%), ventricular septal defect (5%), and persistant ductus arteriosus), broad or webbed neck; cubitus valgus, a combina-tion of pectus carinatum and excavatum; cryptorchidism (60%). The typical facies is characterized by hypotelorism, down-slanting palpebral fissures (95%) with thick hooded eyelids, low set posteriorly rotated ears with a thick helix (90%), a deeply grooved philtrum with high arched palate of the upper lip vermilion border (GSA), high arched palate (45%), micrognathia (25%), excess nuchal skin with low posterior hair line (55%), diamond shaped eyebrows and curly hair. Final height approaches the lower limits of normal at the end of the second decade of life. Behavioral characteristics include failure to thrive in infancy (40%), motor developmental delay (20%), learning disability (15%), language delay (20%), mild hearing loss (12%), and mild mental retardation (up to 35%). A gene for Noonan syndrome - NS-1 is located in the 12q22 - region, but there is genetic heterogenicity. The differential diagnosis include Williams syn-drome, fetal alcohol syndrome, LEOPARD syndrome and Watson syndrome.

M.L. Kulkarni,
Dasari Ramesh

Department of Pediatrics,
J.J.M. Medical College,
Davangere, India.




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