Rothmund-Thomson syndrome is a rare genetic disorder that manifests in early infancy. The range and severity of symptoms may vary from case to case. RTS is typically characterized by skin rash, sparse hair, malformed bones, abnormal clouding of the lenses of the eyes (juvenile cataracts), small stature, and other physical abnormalities. Intelligence is usually normal, but some affected individuals have been reported to have intellectual disability.
Skin and hair findings: Between the ages of approximately three to six months, infants with RTS typically develop Redness (erythema) on the cheeks that may appear as patches or inflamed plaques and may resemble sunburn or even eczema. The Redness may be accompanied by Swelling (edema). In a few cases, the rash may be apparent earlier in life or may develop as late as at two years old. The rash typically spreads to the arms and legs and may or may not involve the buttocks. The trunk and belly are generally spared. Over time and usually by early childhood, the inflammation tends to recede and the skin of affected areas develops into a more chronic pattern of rash known as poikiloderma, characterized by telangiectases (prominent, small, spider-like blood vessels); small spots of atrophy (skin tissue degeneration or thinning); and areas of abnormal skin pigmentation alternating between increased pigment (hyperpigmentation) and decreased pigment (hypopigmentation), giving a lacy, web-like, or mottled appearance.
Sensitivity of the skin to sun exposure (photosensitivity) has been reported in some patients, and the rash tends to affect areas that are more sun-exposed. However, it is important to note that the rash is not always limited to sun-exposed areas (e.g., buttocks). In some cases, affected individuals report a history of blistering (bullae) on the skin that may or may not be related to sun exposure. Blistering tends to diminish as patients reach late childhood.
One of the other skin manifestations of RTS that tends to be more prominent in adulthood is a condition called hyperkeratosis, where certain areas such as the palms and soles, knees and sometimes around the fingers or toes, become thickened and overgrown and develop a rough, wart-like (verrucous) texture. In severe cases, large, verrucous overgrowth of certain areas may cause significant discomfort or restriction of activities.
In addition, many patients with RTS have sparse scalp hair, and some may have complete baldness (alopecia). In many cases, eyebrows, eyelashes, and body hair may also be sparse or absent. In some patients, the nails may be malformed (dystrophic) and/or unusually small (hypoplastic).
Ophthalmologic findings: Between the ages of approximately two to seven years of age, some children with RTS may also develop sudden clouding of the lenses of both eyes (bilateral juvenile cataracts). Such cataracts typically are opaque, semisolid, white dots appearing on one broad or narrow area of an otherwise clear lens (zonular or lamellar cataract). Development of such cataracts may result in severe visual impairment or loss within weeks, and prompt surgical intervention by an eye specialist (ophthalmologist) can usually restore vision.
Growth and development: A large percentage of individuals with RTS experience abnormally slow growth before and after birth (prenatal and postnatal growth retardation), leading to mild to moderate small stature. This small stature is symmetrical for height and weight, and patients have proportional development of the upper and lower body.
Bone and teeth abnormalities: A large percentage of patients have bone abnormalities that may or may not be visible clinically. One of the most obvious abnormalities is a radial ray defect, which is manifest as small, malformed or missing thumbs or shortened forearms. Other bones in the body, particularly those in the arms, hands, and legs, can also be abnormally formed, shortened, or fused, and some of these bone findings can only be seen on x-rays. Some patients may also have characteristic abnormalities of the craniofacial area including a prominent forehead (frontal bossing) or a sunken nasal bridge (saddle nose). Patients may also have decreased bone density (osteopenia or osteoporosis) which in severe cases could lead to fractures. The teeth in patients with RTS may be small or malformed.
Gastrointestinal and feeding problems: Many infants and young children with RTS experience gastrointestinal disturbances including non-specific Vomiting and Diarrhea that are often attributed to intolerance of milk or formula. Some patients require feeding tubes to maintain nutritional intake. However, in virtually all cases, these issues resolve by later childhood.
Cancer: Individuals with RTS have an increased risk of developing cancer, particularly osteosarcoma and non-melanoma skin cancers (squamous and basal cell carcinomas). While these are the most frequent cancers encountered in RTS, there have been a few patients reported who developed squamous cell carcinoma of the head and neck region and hematologic malignancies such as leukemia.
Fertility: Some individuals with RTS may demonstrate hypogonadism, a condition characterized by deficient activity of the gonads (i.e., ovaries in females or testes in males). As a result, affected females may experience irregular menstruation, while both affected males and females may have delayed sexual development. In those affected individuals with hypogonadism, fertility may be reduced; however, some patients (both male and female) have had children.