Hereditary conditions Tutorial

Marfan’s syndrome

Arachnodactyly

Derived from the Greek words “arachne,”, which means “spider”, and “daktylos,” which means “finger.” This condition describes long and slender digits and associated with Marfan’s syndrome and other connective tissue disorders.

Chest wall deformities

Chest wall deformities, including pectus excavatum and pectus carinatum (“pigeon chest”), are a sign of Marfan’s syndrome.

High-arched palate

High-arched or “ogival” palate is a sign of Marfan’s syndrome.

Thumb sign

Positive when the thumb protrudes from the clenched fist, in which the other four digits are flexed over the thumb.

Wrist sign

Positive when the thumb and fifth digit overlap when each are wrapped around the contralateral wrist to form a ring.

 


Pseudoxanthoma elasticum

An autosomal recessive condition characterized by the mineralization of elastic fibers in some tissues. Skin lesions are characterized by yellow papular lesions that resemble xanthomas.

 


MEN type 2 b

Autosomal dominant syndrome characterized by medullary thyroid carcinoma, pheochromocytoma, and mucosal neuromas. Patients may also have a marfanoid body habitus.

 


Ehlers-danlos syndrome

A connective tissue disease that manifests with increased laxity of the joints, tendons, and ligaments. Patients may have blue colored sclera.

 


Neurofibromatosis

Café au lait macules are common and can be a normal finding, but are also seen in a number of neurocutaneous diseases such as neurofibromatosis.

 


Syndactyly

A condition characterized by the fusing of two or more digits.

 


Becker’s Muscular Dystrophy

A genetic syndrome that results in overgrowth of the tissues. Findings include macroglossia and hemihyperplasia.

 


Alkaptonuria

A rare autosomal recessive condition that results in the accumulation of homogentisic acid in the blood and tissues. The classic finding is darkening of the urine when it is left exposed to open air, but other physical manifestations include hyperpigmentation of cartilaginous structures like the ear, as well as the sclera and corneal limbus of the eye.

 


Hereditary hemorrhagic telangiectasia

Mucocutaneous findings- Patients with hereditary hemorrhagic telangiectasia develop arteriovenous malformations, including telangiectasias of the skin and mucosa, usually manifesting as small red dots. These are often seen on the digits, lips, oral cavity, and nose.