Macrocephaly is a condition in which circumference of the human head is abnormally large. It may be pathological or harmless, and can be a familial genetic characteristic. People diagnosed with macrocephaly will receive further medical tests to determine whether the syndrome is accompanied by particular disorders. Those with benign or familial macrocephaly are considered to have megalencephaly.
Brachycephaly is the shape of a skull shorter than average in its species. It is perceived as a cosmetically desirable trait in some domesticated dog and cat breeds, notably the pug and Persian, and can be normal or abnormal in other animal species.
Plagiocephaly, also known as flat head syndrome, is a condition characterized by an asymmetrical distortion of the skull. A mild and widespread form is characterized by a flat spot on the back or one side of the head caused by remaining in a supine position for prolonged periods.
Scaphocephaly, or sagittal craniosynostosis, is a type of cephalic disorder which occurs when there is a premature fusion of the sagittal suture. Premature closure results in limited lateral expansion of the skull resulting in a characteristic long, narrow head. The skull base is typically spared.
Crouzon syndrome is an autosomal dominant genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial arch, which is the precursor of the maxilla and mandible. Since the branchial arches are important developmental features in a growing embryo, disturbances in their development create lasting and widespread effects.
Apert syndrome is a form of acrocephalosyndactyly, a congenital disorder characterized by malformations of the skull, face, hands and feet. It is classified as a branchial arch syndrome, affecting the first branchial arch, the precursor of the maxilla and mandible. Disturbances in the development of the branchial arches in fetal development create lasting and widespread effects.
Craniosynostosis is a condition in which one or more of the fibrous sutures in a young infant's skull prematurely fuses by turning into bone (ossification), thereby changing the growth pattern of the skull. Because the skull cannot expand perpendicular to the fused suture, it compensates by growing more in the direction parallel to the closed sutures. Sometimes the resulting growth pattern provides the necessary space for the growing brain, but results in an abnormal head shape and abnormal facial features. In cases in which the compensation does not effectively provide enough space for the growing brain, craniosynostosis results in increased intracranial pressure leading possibly to visual impairment, sleeping impairment, eating difficulties, or an impairment of mental development combined with a significant reduction in IQ.
Saethre–Chotzen syndrome (SCS), also known as acrocephalosyndactyly type III, is a rare congenital disorder associated with craniosynostosis. This affects the shape of the head and face, resulting in a cone-shaped head and an asymmetrical face. Individuals with SCS also have droopy eyelids (ptosis), widely spaced eyes (hypertelorism), and minor abnormalities of the hands and feet (syndactyly). Individuals with more severe cases of SCS may have mild to moderate intellectual or learning disabilities. Depending on the level of severity, some individuals with SCS may require some form of medical or surgical intervention. Most individuals with SCS live fairly normal lives, regardless of whether medical treatment is needed or not.
Trisomy 8 causes Warkany syndrome 2, a human chromosomal disorder caused by having three copies (trisomy) of chromosome 8. It can appear with or without mosaicism.
Carpenter syndrome, also called acrocephalopolysyndactyly type II, is an extremely rare autosomal recessive congenital disorder characterized by craniofacial malformations, obesity, syndactyly, and polydactyly. Acrocephalopolysyndactyly is a variation of acrocephalosyndactyly that presents with polydactyly.
Jackson–Weiss syndrome (JWS) is a genetic disorder characterized by foot abnormalities and the premature fusion of certain bones of the skull (craniosynostosis), which prevents further growth of the skull and affects the shape of the head and face. This genetic disorder can also sometimes cause intellectual disability and crossed eyes. It was characterized in 1976.
Acrocephalosyndactyly is a group of congenital conditions characterized by irregular features of the face and skull (craniosynostosis) and hands and feet (syndactyly). Craniosynostosis occurs when the cranial sutures, the fibrous tissue connecting the skull bones, fuse the cranial bones early in development. Cranial sutures allow the skull bones to continue growing until they fuse at age 24. Premature fusing of the cranial sutures can result in alterations to the skull shape and interfere with brain growth. Syndactyly occurs when digits of the hands or feet are fused together. When polydactyly is also present, the classification is acrocephalopolysyndactyly. Polydactyly occurs when the hands or feet possess additional digits. Acrocephalosyndactyly is usually diagnosed after birth, although prenatal diagnosis is sometimes possible if the genetic variation is present in family members, as the conditions are typically inherited in an autosomal dominant pattern Treatment often involves surgery in early childhood to correct for craniosynostosis and syndactyly.
Twist-related protein 1 (TWIST1) also known as class A basic helix–loop–helix protein 38 (bHLHa38) is a basic helix-loop-helix transcription factor that in humans is encoded by the TWIST1 gene.
Kleeblattschaedel is a rare malformation of the head where there is a protrusion of the skull and broadening of the face. This condition is a severe type of craniosynostosis.
Craniosynostosis and dental anomalies is an autosomal recessive syndrome characterized by craniosynostosis, maxillary hypoplasia, and dental anomalies. Dental anomalies seen in this condition include malocclusion, delayed and ectopic tooth eruption, and/or supernumerary teeth. Syndactyly, clinodactyly, and other digit anomalies may also be present.
Low anterior hairline is a condition in which the frontal hairline which defines the top and sides of the forehead is unusually low. This can mean that either the distance between the trichion (hairline) and glabella at the midline is more than 2 SD below the mean, or that this distance is apparently (subjectively) decreased.
Flat forehead is a condition in which the surface of the forehead is unusually flat.
15q overgrowth syndrome is a rare partial autosomal trisomy/tetrasomy syndrome. The condition was first identified in a 2009 report.
Brachyturricephaly is a form of complex craniosynostosis in which the head has both an abnormally high vertical height and a shortened length from anterior to posterior. Malformations of the occipital region are also often present.
