Genetic Disorders

Genetics Diseases
Tania Alejandra Jimenez Godines

Hadju Cheney Syndrome
Ehlers-Danlos Syndrome
Turner Syndrome
Klinefelter's Syndrome
Cri Du Chat Syndrome

Hajdu Cheney

Hajdu-Cheney Syndrome is a rare connective tissue disorder. Connective tissue is strong fibrous tissue that supports and joins other body tissues and parts. Abnormal development of bones, joints, and teeth alsooccurs. A decrease in bone mass and changes in the skull and jawbone are also features of this syndrome.

An osteolytic syndrome with skull deformities, characteristics facies, osteoporosis, premature loss of teeth, joint laxity, short stature, dissolution of the terminal phalanges, hearing loss, and a hoarse voice. Most patients have a normal mental development but some are mildly retarded.Approximately 70 cases have been reported worldwide. Most of them are men.

Symptoms and signs

Hajdu–Cheney syndrome causes short stature and extreme bone flexibility. The disorder can also cause mild cognitive delays, such as delayed speech acquisition. Fetuses with Hajdu–Cheney syndrome often will not be seen to unclench their hands on obstetrical ultrasound. They may also have low set ears andtheir eyes may be farther apart than on a usual child, called hypertelorism. Children's heads can have some deformities in their shape and size (plagiocephaly). Early tooth loss and bone deformities, such as serpentine tibias and fibulas, are also common in those affected.

In addition, patients with HCS frequently have skull deformities, short stature, joint laxity, reduction of bone mass(osteoporosis) and other signs. Most affected individuals have normal mental development but a small proportion show mild mental retardation.

Although the majority of cases are of unknown cause, the presence of multiple cases in one family suggests that autosomal dominant genetic transmission may be possible.
• Head and Neck: Macrocephaly, enlarged supraorbital ridges, basilar invagination,squamous protuberance of occipital bone, bathrocephaly, dolichocephaly, wide cranial sutures, wormian bones, depression of anterior fontanels, dysgenesis or genesis of frontal sinuses, enlarged and J-shaped sella turcica, position of mandibular condyles anterior to glenoid fossae, resorption of condylar heads or mandibular rami, absent mandibular chin button, midfacial hypoplasia, and mandibularmicrognathia.
• Eyes: Cataract, nystagmus, exophthalmos, hypertelorism, epicanthal folds, abducent palsy, disk pallor, optic atrophy, synophrys, and thick coarse eyebrows. Nose Resorption of anterior nasal spine and short philtrum Mouth and Oral Structures Highly arched palate, uvular abnormalities, cleft palate, malocclusion, and missing and loose teeth
• Hand and Foot: Club foot,acro-osteolysis with short distal portions of fingers and toes and broad stubby fingers, narrowing of metacarpophalangeal and metatarsophalangeal spaces, osetolysis of radius, and hyperflexible interphalangeal joints.
• Extremities Joint laxity, genu valgum, curving of tibiae and fibulae, fractures, and hip and joint dislocations
• Spine Compression fractures, fish-bone vertebrae, denseintervertebral disks, fission of vertebrae, and kyphosis or scoliosis
• Bones and Joints Osteoporosis
• Skin Appendages Generalized hirsutism with thick and coarse scalp hair and, hairline on forehead and nape, and wide nails
• Nervous System Impaction of cerebellum into foramen magnum, occipital headache, hydrocephaly, and progressive involvement of cranial nerves
• Cardiovascular SystemPatent Ductus arteriosus, ventricular septal defect, atrial septal defect, and hypertension
• Respiratory System Upper airway obstruction
• Hematopoietic System Splenomegaly, Development: growth, motor and mental retardation
• Behavior and Performance Myopia, deafness, gruff or high-pitched voice
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Treatment

Since about 2002, some patients with this disorder have been...