Subluxated lens, thin elongated, hyperextensible extremities and aortic aneurysm are the characteristic clinical features of
(A) Marfan's syndrome # MARFAN'S SYNDROME is a disorder of connective tissue (elastin). The gene called fibrillin is on chromosome 15. Inheritance is autosomal ominant. Sporadic cases may occur. The patients are tall and slender. Extremities especially the fingers and toes are long and thin. The muscles are markedly hypotonic and joints are hyperextendible. At times the disorder may be associated with arthrogryposis (contraction of joints in flexion due to fibrous ankylosis). There may be subluxation of the lens and other ocular abnormalities e.g., cataract, coloboma, squint, nystagmus and megalocornea. Deformities of the chest and spine may be present. Other associated anomalies include aortic cystic medionecrosis leading to aortic dilatation and other valvular deformities. Intelligence is normal. It should be distinguished from cases of homocystinuria, which also may present with ectopia lentis and similar bone changes, but has associated mental retardation. The basic manifestations are joint hypermobility, skin hyperextensibility, dystrophic scarring of the skin and easy bruising, and connective tissue fragility. Wound healing is delayed and there are freely movable subcutaneous nodules. Molecular genetics has helped to characterize 11 different types of Ehlers-Danlos syndrome. Homocystinuria is a relatively common metabolic error with autosomal recessive inheritance. In the most common situation, Type 1, cystathionine is not synthesized from homocysteine and serine because the enzyme cystathionine synthetase in the liver is deficient. Although the precursor, homocysteine accumulates in the tissues, it is rapidly oxidized to homocystine. The usual age of presentation is 3-4 years. The patients develop subluxation of the lens, recurrent thromboembolic episodes and have marfanoid features. Klinefelter syndrome is characterized by tall thin stature, small testes and small phallus, with the chromosomal karyotype of 47 XXY. Behavioral and psychiatric disorders and mental retardation are common.
Marfan's syndrome
Ehler Danlos syndrome
Homocystienuria
Klienfelter's syndrome.
Miscellaneous