PEDBASE.org - The Pediatric Database - Detailed information of CARTILAGE-HAIR HYPOPLASIA

CARTILAGE-HAIR HYPOPLASIA

DEFINITION:

A hereditary disorder characterizedby short limbed (micromelic) dwarfism and a primary T cell disorder.

EPIDEMIOLOGY:

incidence: rare
age of onset:
- infancy
risk factors:
- familial - autosomal recessive
  - chrom.#: ?
  - gene: ?
- M = F
- Amish, Finnish

PATHOGENESIS:

1. Background

unknown etiology
also called Metaphyseal Chondrodysplasia (McKusick Type)

2. Genetic Defect

genetic defect -> bone dysplasia -> musculoskeletal manifesta-tions and impairment of T-cell function due to an intrinsic defect in cell proliferation

CLINICAL FEATURES:

1. Musculoskeletal Manifestations

1. Infancy

short, broad hands and feet
short, brittle fingernails and toenails
limited elbow extension

2. Childhood

short-limbed (micromelic) dwarfism
bowing of the femur and tibia
equinovarus deformity of the feet due to overgrowth of the fibulae
osteoarthritis

2. Cutaneous Manifestations

redundant skin folds around the neck and extremities at birth
fine, sparse usually light-coloured hair, eyebrows, and lashes
hair lacks a central, pigmented core
scanty secondary hair growth

3. Immunodeficiency Manifestations

limited susceptibility to viral infections - vaccinia, vari-cella
chronic candidiasis is not a feature

4. Other Manifestations

1. Gastrointestinal

dental anomalies
malabsorption
Hirschsprung Disease

2. Hematologic

congenital anemia

INVESTIGATIONS:

1. Serum

absence of T cell function
normal immunoglobulins
neutropenia and/or lymphopenia

2. Imaging Studies

1. Skeletal X-Rays

metaphyseal chondrodysplasia with prominant hand, foot, and knee involvement
cupping of the anterior ends of the ribs
distal overgrowth of the fibula
short long bones with flared ends
delayed carpal ossification

MANAGEMENT:

1. Supportive

no treatment for underlying disease
multidisciplinary approach
- Paediatrics, Orthopedics, Physiotherapy
- genetic counselling
avoid smallpox vaccinations
leukocyte interferon for varicella infections
bone marrow transplantation has been successful
thymus transplantation is experimental

2. Prognosis

normal life span
average adult height: 120 cm

Pediatric Database - CARTILAGE-HAIR HYPOPLASIA

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