What are the signs and symptoms of Hallermann-Streiff syndrome? The signs and symptoms of Hallermann-Streiff syndrome vary in range and severity among affected individuals. The main features of the condition include abnormalities of the skull and facial bones with distinctive facial characteristics (craniofacial abnormalities); ocular (eye) abnormalities; dental abnormalities; and/or short stature. Craniofacial features may include a short, broad head (brachycephaly) with an unusually prominent forehead and/or sides of the skull (frontal bossing); a small, underdeveloped lower jaw (micrognathia); a narrow, highly arched roof of the mouth (palate); and a thin, pinched, tapering nose (beaked nose). Ocular abnormalities may include clouding of the lenses of the eyes at birth (congenital cataracts); unusually small eyes (microphthalmia); and/or other abnormalities. Dental defects may include the presence of teeth at birth (natal teeth) and/or absence, malformation, or improper alignment of teeth. Hypotrichosis (sparse hair) is present in about 80 percent of affected individuals. Other features may include skin atrophy of the face, and/or hypoplasia (underdevelopment) of the clavicles and ribs. Intellectual disability is present in some cases (approximately 15 percent). In many cases, additional abnormalities are present. The Human Phenotype Ontology provides the following list of signs and symptoms for Hallermann-Streiff syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of the clavicle 90% Abnormality of the ribs 90% Alopecia 90% Aplasia/Hypoplasia affecting the eye 90% Aplasia/Hypoplasia of the skin 90% Cataract 90% Convex nasal ridge 90% Frontal bossing 90% Reduced bone mineral density 90% Short stature 90% Abnormality of hair texture 50% Abnormality of the fontanelles or cranial sutures 50% Abnormality of the nares 50% Abnormality of the palate 50% Advanced eruption of teeth 50% Glossoptosis 50% Hypoplasia of the zygomatic bone 50% Increased number of teeth 50% Narrow mouth 50% Recurrent fractures 50% Telecanthus 50% Visual impairment 50% Intellectual disability 15% Abdominal situs inversus 7.5% Aplasia/Hypoplasia of the cerebellum 7.5% Choanal atresia 7.5% Clinodactyly of the 5th finger 7.5% Cognitive impairment 7.5% Congestive heart failure 7.5% Cryptorchidism 7.5% Glaucoma 7.5% Hypothyroidism 7.5% Inflammatory abnormality of the eye 7.5% Microcephaly 7.5% Myopia 7.5% Nystagmus 7.5% Respiratory insufficiency 7.5% Short foot 7.5% Short palm 7.5% Strabismus 7.5% Tracheomalacia 7.5% Abnormality of the hand - Abnormality of the nasopharynx - Blue sclerae - Brachycephaly - Choreoathetosis - Chorioretinal coloboma - Decreased number of sternal ossification centers - Dental malocclusion - Dermal atrophy - Dolichocephaly - Dry skin - Fine hair - Generalized tonic-clonic seizures - High palate - Hyperactivity - Hyperlordosis - Hypotrichosis of the scalp - Iris coloboma - Joint hypermobility - Low-set ears - Malar flattening - Metaphyseal widening - Microphthalmia - Narrow nose - Narrow palate - Natal tooth - Obstructive sleep apnea - Optic nerve coloboma - Parietal bossing - Pectus excavatum - Platybasia - Proportionate short stature - Pulmonary hypertension - Recurrent pneumonia - Recurrent respiratory infections - Scoliosis - Selective tooth agenesis - Slender long bone - Small for gestational age - Sparse eyebrow - Sparse eyelashes - Sparse hair - Spina bifida - Sporadic - Telangiectasia - Thin calvarium - Thin ribs - Thin vermilion border - Underdeveloped nasal alae - Wormian bones - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.